Difference between pages "How to Make Soap" and "How to Build a Yoghurt Incubator for Small-Business Production"

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==Short Description==
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*'''Problem:''' Production of Yogurt, one needs to construct a yogurt incubator
 +
*'''Idea:''' Two methods to construct a yogurt incubator
 +
*'''Difficulty:''' Easy
 +
*'''Price Range:''' Less than 10 US$
 +
*'''Material Needeed:''' Water, milk
 +
*'''Geographic Area:''' Global
 +
*'''Competencies:'''
 +
*'''How Many people?''' One
 +
*'''How Long does it take?'''
  
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+
=Yoghurt Incubator - Manual and Semi Automatic - =
−
=Soapmaking - Technical Brief=
 
  
 
<div class="booktext">
 
<div class="booktext">
  
−
'''PRACTICAL ACTION'''<br />'''Technology challenging poverty'''
+
<center>'''PRACTICAL ACTION'''<br />'''Technology challenging poverty'''</center>
  
 
</div>
 
</div>
  
−
==Introduction==
+
==Background==
  
 
<div class="booktext">
 
<div class="booktext">
  
−
With practice, soapmaking is not difficult and is suitable as a small-scale business. It uses simple equipment and vegetable oils or animal fats as raw materials, each of which is likely to be locally available in most countries. However, it is more difficult to produce high-quality hard soap, which in some countries is necessary to compete with imported products or those produced by large-scale manufacturers. There are also certain hazards in producing soap, which any potential producer must be aware of to avoid injury. This technical brief describes the procedures needed to make a variety of simple soaps and includes a number of recipes for different types of soap.
+
Yoghurt manufacturing is a popular small-scale food processing endeavour. Yoghurt is relatively simple to produce, can be done with a small amount of capital and there is a good demand for it in the market. According to the technical inquiries received by the Cathy Rich Memorial Food Processing Training Centre, 20% of the requests from small-scale entrepreneurs are for information on making yoghurt. The most important feature and function of this process is the incubation of the mixture since it acquires the needed flavour as this stage.
  
−
<center>
+
There are no small-scale industrial yoghurt incubators produced in the local market. The yoghurt incubators used by large businesses are too expensive and have a much larger capacity than is necessary for small-scale food processors (SSFP). Plus SSFPs do not have the capital or the space to accommodate an industrial sized incubator.
  
−
[[Image:p01.jpg]]<br /> Figure 1: Bina Baroi with some of her finished soap products after soapmaking training from Practical Action Bangladesh. ©Zul/Practical Action
+
The SSFPs use makeshift incubators: rigifoam or wooden boxes, where the heat cannot be regulated or maintained, and do not produce good quality yoghurt. These makeshift models could only accommodate 250 cups per batch. They are also difficult to clean and are unhygienic. Therefore the SSFPs could not sell their produce and could not compete with the large scale producers.
  
−
</center></div>
+
Practical Action South Asia (then called ITDG) along with the Cathy Rich Memorial Food Processing Centre responded to a request by SSFPs to design an appropriate incubator. It has improved the standard of the yoghurt produced, it is low in cost, has a greater capacity and easy to operate and maintain.
 +
 
 +
</div>
  
−
==Ingredients==
+
==The incubators==
  
 
<div class="booktext">
 
<div class="booktext">
  
−
There are three main ingredients in plain soap - oil or fat (oil is simply liquid fat), lye (or alkali) and water. Other ingredients may be added to give the soap a pleasant odour or colour, or to improve its skin-softening qualities. Almost any fat or non-toxic oil is suitable for soap manufacture. Common types include animal fat, avocado oil and sunflower oil. Lyes can either be bought as potassium hydroxide (caustic potash) or from sodium hydroxide (caustic soda), or if they are not available, made from ashes. Some soaps are better made using soft water, and for these it is necessary to either use rainwater or add borax to tap water. Each of the above chemicals is usually available from pharmacies in larger towns.
+
The yoghurt incubators developed had slight modifications to the industrial incubator. Practical Action South Asia designed two models: one which is manual and one that is semi automatic: The basic structure is the same with the difference being the thermostat unit.
−
<center>
 
−
{| border="1" cellpadding="5"
 
−
|- valign="top"
 
−
| valign="top" |
 
−
'''Caution!'''
 
  
−
Lyes are extremely caustic. They cause burns if splashed on the skin and can cause blindness if splashed in the eye. If drunk, they can be fatal.
+
The incubators introduced by Practical Action South Asia aluminium frames with rigifoam insulation. The rigifoam insulation is for heat retention which increases the efficiency and reduces the electricity consumption.
  
−
Care is needed when handling lyes and 'green' (uncured) soap. Details of the precautions that should be taken are given below.
+
The incubator has two chambers with 6 removable shelves in each chamber. Bulbs are installed at the base of the incubator to supply the required heat.
  
−
Because of these dangers, keep small children away from the processing room while soap is being made.
+
The incubator has a glass front so that it can be judged visually when the yoghurt has matured and ready to be taken out. In the manual model, the heat source (the bulbs) have to be turned on and off as required and the incubator temperature needs to be monitored.
−
|}
 
−
</center>
 
  
−
==How to make lye from ashes==
+
In the semi-automatic version, the thermostat turns off when the required temperature is reached and does not need to be monitored.
  
−
<div class="booktext">
+
The incubator could have an internal fan which helps regulate the heat (by 4-5 degrees) but optional. If the incubator has the fan, it will increase the cost of construction, operation (electricity) and maintenance. This would keep the same flavour and consistency in all the yoghurt cups in the incubator.
  
−
Commercial lyes can be bought in tins from pharmacies in larger towns, and these are a standard strength to give consistent results. However, if they are not available or affordable, lye can also be made from ashes. Fit a tap near to the bottom of a large (e.g. 250 litre) plastic or wooden barrel/tub. Do not use aluminium because the lye will corrode it and the soap will be contaminated. Make a filter inside, around the tap hole, using several bricks or stones covered with straw. Fill the tub with ashes and pour boiling water over them until water begins to run from the tap. Then shut the tap and let the ashes soak. The ashes will settle to less than one quarter of their original volume, and as they settle, add more ashes until the tub is full again. Ashes from any burned plant material are suitable, but those from banana leaf/stem make the strongest lye, and those from apple wood make the whitest soap.
+
In the semi-automatic incubator, the internal chambers can be sterilised easily by setting the thermostat to 100°C. This allows the production process to be more hygienic by removing any unwanted bacteria that could spoil the yoghurt or alter its taste.
  
−
If a big barrel is not available, or smaller amounts of soap are to be made, a porcelain bowl or plastic bucket can be used. Fill the bucket with ashes and add boiling water, stirring to wet the ashes. Add more ashes to fill the bucket to the top, add more water and stir again. Let them stand for 12 - 24 hours, or until the liquid is clear, then carefully pour off the clear lye.
+
The introduced yoghurt incubator has these advantages:<br />
−
 
 
−
The longer the water stands before being drawn off, the stronger the lye will be. Usually a few hours will be enough. Lye that is able to cause a fresh egg to float can be used as a standard strength for soap-making. The strength of the lye does not need to always be the same, because it combines with the fat in a fixed proportion. If a weak lye is used, more lye can be added during the process until all the fat is saponified<sup>1</sup>.<br />
 
  
 
<blockquote>
 
<blockquote>
  
−
<sup>1</sup> saponification is the name given to the chemical reaction in which lye and fat are converted into one substance -soap
+
• The heat can be regulated<br /> • It is insulated to minimise heat losses<br /> • It can be easily cleaned after every batch<br /> • It can be sterilised without dismantling<br /> • It can be fabricated and maintained locally<br /> • It is more efficient and durable
  
 
</blockquote></div>
 
</blockquote></div>
  
−
==How to make potash==
+
==Technical details==
−
 
 
−
<div class="booktext">
 
−
 
 
−
Potash is made by boiling down the lye water in a heavy iron kettle. After the water is driven off, a dark, dry residue known as 'black salts' remains. This is then heated until it melts and the black impurities are burned away to leave a greyish-white substance. This is potash. It can be stored for future soapmaking in a moisture-proof pot to prevent it absorbing water from the air.
 
−
 
 
−
</div>
 
−
 
 
−
==How to make soda lye and caustic soda==
 
  
−
<div class="booktext">
+
<div class="booktext"><div align="left">
−
 
 
−
Mix 1 part quicklime with 3 parts water to make a liquid that has the consistency of cream. Dissolve 3 parts sal soda in 5 parts boiling water, and add the lime cream, stirring vigorously. Keep the mixture boiling until the ingredients are thoroughly mixed. Then allow it to cool and settle, and pour off the lye. Discard the dregs in the bottom. Caustic soda is produced by boiling down the lye until the water is evaporated and a dry, white residue is left in the kettle. Most commercial lyes are caustic soda, and these can be bought and substituted for homemade lye to save time. They are supplied in tins and the lids should be kept tightly fitted to stop the lye absorbing water from the air and forming a solid lump.
 
  
 
{| border="1" cellpadding="5"
 
{| border="1" cellpadding="5"
 +
|- valign="top"
 +
| colspan="3" valign="top" |
 +
<center>'''Material required'''</center>
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
'''Care when using lyes, potash or caustic soda'''
+
Material
−
 
 
−
You should always take precautions when handling these materials as they are dangerous. Be especially careful when adding them to cold water, when stirring lye water, and when pouring the liquid soap into moulds. Lyes produce harmful fumes, so stand back and avert your head while the lye is dissolving. Do not breath lye fumes. It is worth investing in a pair of rubber gloves and plastic safety goggles. You should also wear an apron or overalls to protect your clothes. If lye splashes onto the skin or into your eyes, wash it off immediately with plenty of cold water.
 
−
 
 
−
When lye is added to water the chemical reaction quickly heats the water. Never add lye to hot water because it can boil over and scald your skin. Never add water to lye because it could react violently and splash over you.
 
−
|}
 
−
 
 
−
==How to prepare tallow==
 
−
 
 
−
<div class="booktext">
 
−
 
 
−
Cut up beef suet, mutton fat or pork scraps and heat them over a low heat. Strain the melted fat through a coarse cloth, and squeeze as much fat as possible out of the scraps.
 
−
 
 
−
Clean the melted fat by boiling it in water. Use twice as much water as fat, add a tablespoon of salt per 5 kg fat, and boil for ten minutes, stirring thoroughly all the time. Allow it to cool and form a hard cake on top of the water. Lift off the cake of fat and scrape the underside clean. This is then ready to store or use in a soap recipe.
 
−
 
 
−
</div>
 
−
 
 
−
==How to prepare oil==
 
−
 
 
−
<div class="booktext">
 
−
 
 
−
Vegetable oils can be extracted from oilseeds, nuts or some types of fruit (see Table 1 and the separate Technical Brief 'Oil Extraction'). They can be used alone or mixed with fat or other types of oil. Note: solid fats and 'saturated' oils (coconut, palm, palm kernel) are more suitable for soapmaking. 'Unsaturated' oils (e.g. safflower, sunflower) may produce soap that is too soft if used alone (see Table 2) and are not recommended.
 
−
 
 
−
</div>
 
−
 
 
−
==Soapmaking==
 
−
 
 
−
<div class="booktext">
 
−
 
 
−
There are two types of soap: soft soap and hard soap. Soft soap can be made using either a cold process or a hot process, but hard soap can only be made using a hot process. To make any soap it is necessary to dilute the lye, mix it with the fat or oil, and stir the mixture until saponification takes place (in the processes described below, the word 'fat' is used to mean either fat or oil). The cold process may require several days or even months, depending upon the strength and purity of the ingredients, whereas the hot process takes place within a few minutes to a few hours.
 
−
 
 
−
'''''Dispose of soap-making wastes carefully outdoors, do not put them in the drain.'''''
 
−
 
 
−
<div align="left">{| border="1" cellpadding="5"
 
−
|- valign="top"
 
 
| valign="top" |
 
| valign="top" |
−
'''Fats'''
+
Specification
 
| valign="top" |
 
| valign="top" |
−
'''Oils'''
+
Quantity
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
Goat fat
+
Aluminium Angles
 
| valign="top" |
 
| valign="top" |
−
Canola
+
½” X ½”, 12ft lengths
−
|- valign="top"
 
 
| valign="top" |
 
| valign="top" |
−
Lanolin
+
03 Nos.
−
| valign="top" |
 
−
Coconut
 
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
Lard
+
Aluminium Angles
 
| valign="top" |
 
| valign="top" |
−
Cottonseed
+
¾” X ¾”, 12ft lengths
−
|- valign="top"
 
 
| valign="top" |
 
| valign="top" |
−
Mutton fat
+
10 Nos.
−
| valign="top" |
 
−
Palm
 
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
Pork fat
+
Aluminium Tee Sections
−
| valign="top" |
 
−
Palm kernel
 
−
|- valign="top"
 
 
| valign="top" |
 
| valign="top" |
−
Suet
+
1” X 1” , 12ft lengths
 
| valign="top" |
 
| valign="top" |
−
Soybean
+
06 Nos.
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
Tallow
+
Aluminium “U” Sections
−
|
 
−
|}</div>
 
−
 
 
−
Table 1: Types of fats and oils used in soapmaking
 
−
 
 
−
</div>
 
−
 
 
−
==Soft soap==
 
−
 
 
−
<div class="booktext">
 
−
 
 
−
'''Cold process'''
 
−
 
 
−
A simple recipe for soft soap uses 12 kg of fat, 9 kg of potash and 26 litres of water. Dissolve the potash in the water and add it to the fat in a wooden tub or barrel. For the next 3 days, stir it vigorously for about 3 minutes several times a day, using a long wooden stick or paddle. Keep the paddle in the mixture to prevent anyone accidentally touching it and being burned. In a month or so the soap is free from lumps and has a uniform jelly-like consistency. When stirred it has a silky lustre and trails off the paddle in slender threads. Then the soap is ready to use and should be kept in a covered container.
 
−
 
 
−
'''Boiling process'''
 
−
 
 
−
Soft soap is also made by boiling diluted lye with fat until saponification takes place. Using the same amounts as above, put the fat into a soap kettle, add sufficient lye to melt the fat and heat it without burning. The froth that forms as the mixture cooks is caused by excess water, and the soap must be heated until this is evaporated. Continue to heat and add more lye until all the fat is saponified. Beat the froth with the paddle and when it ceases to rise, the soap falls lower in the kettle and takes on a darker colour. White bubbles appear on the surface, making a peculiar sound (the soap is "talking"). The thick liquid then becomes turbid and falls from the paddle with a shining lustre. Further lye should then be added at regular intervals until the liquid becomes a uniformly clear slime. The soap is fully saponified when it is thick and creamy, with a slightly slimy texture. After cooling, it does not harden and is ready to use.
 
−
 
 
−
To test whether the soap is properly made, put a few drops from the middle of the kettle onto a plate to cool. If it remains clear when cool it is ready. However, if there is not enough lye the drop of soap is weak and grey. If the deficiency is not so great, there may be a grey margin around the outside of the drop. If too much lye has been added, a grey skin will spread over the whole drop. It will not be sticky, but can be slid along the plate while wet. In this case the soap is overdone and more fat must be added.
 
−
 
 
−
'''Hard soap'''
 
−
 
 
−
The method for making hard soap is similar to that for making soft soap by the boiling process, but with additional steps to separate water, glycerine, excess alkali and other impurities from the soap. The method requires three kettles: two small kettles to hold the lye and the fat, and one large enough to contain both ingredients without boiling over.
 
−
 
 
−
Put the clean fat in a small kettle with enough water or weak lye to prevent burning, and raise the temperature to boiling. Put the diluted lye in the other small kettle and heat it to boiling. Heat the large kettle, and ladle in about one quarter of the melted fat. Add an equal amount of the hot lye, stirring the mixture constantly. Continue this way, with one person ladling and another stirring, until about two-thirds of the fat and lye have been thoroughly mixed together. At this stage the mixture should be uniform with the consistency of cream. A few drops cooled on a glass plate should show neither separate globules of oil or water droplets. Continue boiling and add the remainder of the fat and lye alternately, taking care that there is no excess lye at the end of the process. Boiled hard soaps have saponified when the mixture is thick and ropy and slides off the paddle.
 
−
 
 
−
Up to this point, the process is similar to boiling soft soap, but the important difference in making hard soap is the addition of salt at this point. This is the means by which the creamy emulsion of oils and lye is broken up. The salt has a stronger affinity for water than it has for soap, and it therefore takes the water and causes the soap to separate. The soap then rises to the surface of the lye in curdy granules. The spent lye contains glycerine, salt and other impurities, but no fat or alkali. Pour the honey-thick mixture into soap moulds or shallow wooden boxes, over which loose pieces of cloth have been placed to stop the soap from sticking. Alternatively, the soap may be poured into a tub which has been soaked overnight in water, to cool and solidify. Do not use an aluminium container because the soap will corrode it. Cover the moulds or tub with sacks to keep the heat in, and let it set for 2 - 3 days.
 
−
 
 
−
When cold the soap may be cut into smaller bars with a smooth, hard cord or a fine wire. It is possible to use a knife, but care is needed because it chips the soap. Stack the bars loosely on slatted wooden shelves in a cool, dry place and leave them for at least 3 weeks to season and become thoroughly dry and hard.
 
−
 
 
−
'''''Be careful! Uncured or 'green' soap is almost as caustic as lye. Wear rubber gloves when handling the hardened soap until it has been cured for a few weeks.'''''
 
−
 
 
−
</div>
 
−
 
 
−
==Problems in soapmaking==
 
−
 
 
−
<div class="booktext">
 
−
 
 
−
Problems that can occur in soapmaking and their possible causes are described in Table 2.
 
−
 
 
−
<div align="left">
 
−
{| border="1" cellpadding="5" cellspacing="0"
 
−
|- valign="top"
 
 
| valign="top" |
 
| valign="top" |
−
'''Problem'''
+
12ft lengths
 
| valign="top" |
 
| valign="top" |
−
'''Possible causes'''
+
01 No.
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
Soap will not thicken quickly enough
+
Aluminium sheet
 
| valign="top" |
 
| valign="top" |
−
Not enough lye, too much water, temperature too low, not stirred enough or too slowly, too much unsaturated oil (e.g. sunflower or safflower).
+
gauge 20 x 8" x 4"
−
|- valign="top"
 
 
| valign="top" |
 
| valign="top" |
−
Mixture curdles while stirring
+
01.5 Nos.
−
| valign="top" |
 
−
Fat and/or lye at too high temperature, not stirred enough or too slowly.
 
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
Mixture sets too quickly, while in the kettle
+
Welded Mesh
 
| valign="top" |
 
| valign="top" |
−
Fat and lye temperatures too high.
+
75 mm2
−
|- valign="top"
 
 
| valign="top" |
 
| valign="top" |
−
Mixture is grainy
+
04 m2
−
| valign="top" |
 
−
Fat and lye temperature too hot or too cold, not stirred enough or too slowly.
 
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
Layer of oil forms on soap as it cools
+
Plain Glass
 
| valign="top" |
 
| valign="top" |
−
Too much fat in recipe or not enough lye.
+
0.8 m2
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
Clear liquid in soap when it is cut
+
Bulbs
 
| valign="top" |
 
| valign="top" |
−
Too much lye in recipe, not stirred enough or too slowly.
+
40W
−
|- valign="top"
 
 
| valign="top" |
 
| valign="top" |
−
Soft spongy soap
+
10 Nos.
−
| valign="top" |
 
−
Not enough lye, too much water, or too much unsaturated oil
 
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
Hard brittle soap
+
Dial Type Thermometer
 
| valign="top" |
 
| valign="top" |
−
Too much lye
+
0°- 100°C
−
|- valign="top"
 
 
| valign="top" |
 
| valign="top" |
−
Soap smells rancid
+
01 No.
−
| valign="top" |
 
−
Poor quality fat, too much fat or not enough lye.
 
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
Air bubbles in soap
+
Thermostat*
−
| valign="top" |
 
−
Stirred too long
 
−
|- valign="top"
 
 
| valign="top" |
 
| valign="top" |
−
Mottled soap
+
Wall mounted, adjustable
 
| valign="top" |
 
| valign="top" |
−
Not stirred enough or too slowly or temperature fluctuations during curing.
+
01 No.
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
Soap separates in mould, greasy surface layer on soap
+
Electric fan**
−
| valign="top" |
 
−
Not enough lye, not boiled for long enough, not stirred enough or too slowly
 
−
|- valign="top"
 
 
| valign="top" |
 
| valign="top" |
−
White powder on cured soap
+
Low profile box fan - vertical operation
 
| valign="top" |
 
| valign="top" |
−
Hard water, lye not dissolved properly, reaction with air.
+
01 No.
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
Warped bars
+
Wires, teflon sleeving, connectors, self tapping screws etc.
 
| valign="top" |
 
| valign="top" |
−
Drying conditions variable.
+
As required
 
|}
 
|}
  
−
Table 2: Problems in soapmaking<br /> (Adapted from website <u>http://www.colebrothers.com/soap</u> in list of further information below)
+
</div><blockquote>
  
−
</div>
+
<nowiki>* The thermostat is needed for the semi-automatic model</nowiki><br /> ** The fan is optional
  
−
==To improve hard soap==
+
</blockquote></div>
  
−
<div class="booktext">
+
==Construction==
  
−
A better quality soap may be made by re-melting the product of the first boiling and adding more fats or oils and lye as needed, then boil the whole until saponification is complete. The time required for this final step will depend on the strength of the lye, but 2 - 4 hours' boiling is usually necessary. If pure grained fat and good quality white lye are used, the resulting product will be a pure, hard white soap that is suitable for all household purposes. Dyes, essences or essential oils can be added to the soap at the end of the boiling to colour it or to mask the 'fatty lye' smell and give a pleasant odour.
+
<div class="booktext"><blockquote>
  
−
</div>
+
• The incubator frame is rectangular with the glass sheeting in the front.<br /> • The thermostat is attached to the external frame<br /> • The size, shape and position of the trays are as shown in the drawings<br /> • Bulbs will be placed at the base of the incubator (internally).
  
−
==Hard soap recipes==
+
</blockquote></div>
  
−
<div class="booktext">
+
==Specific requirements==
  
−
The simplest and cheapest type of soap is plain laundry soap, but a few inexpensive ingredients can be used to soften the water or to perfume the product and create fine toilet soaps too. The following recipes are a few examples of easily made soaps. There are many more recipes in the information sources given at the end of this Technical Brief.
+
<div class="booktext"><blockquote>
  
−
'''Simple kitchen soap'''
+
• Electricity - 240V supply<br /> • Floor Area - 600mm x 1225mm
  
−
Dissolve 1 can of commercial lye in 5 cups cold water and allow it to cool. Meanwhile mix 2 tablespoons each of powdered borax and liquid ammonia in _ cup water. Melt 3 kg fat, strain it and allow it to cool to body temperature. Pour the warm fat into the lye water and while beating the mixture, gradually add the borax and ammonia mixture. Stir for about 10 -15 minutes until an emulsion is formed, and pour the mixture into a mould to cool.
+
</blockquote></div>
  
−
'''Boiled hard white soap'''
+
==Capacity==
  
−
Dissolve 0.5 kg potash lye in ''5'' litres of cold water. Let mixture stand overnight, then pour the clear liquid into a second 5 litres of hot water and bring it to a boil. Pour in 2 kg of hot melted fat in a thin stream, stirring constantly until an emulsion is formed. Simmer for 4 - 6 hours with regular stirring, and then add ''5'' litres of hot water in which 1 cup of salt is dissolved. Test to ensure that the mixture is saponified by lifting it on a cold knife blade, to ensure that it is ropy and clear. or
+
<div class="booktext"><blockquote>
  
−
Dissolve 0.5 kg potash in 2 litres of cold water. Heat and add 2.5 kg melted fat, stirring constantly. Let the mixture stand for 24 hours and add 5 litres boiling water. Place it on a low heat and boil with constant stirring until it is saponified.
+
• The incubator has 2 chambers with 6 trays each and one tray hold 42
  
−
'''Labour-saving soap'''
+
• The incubator can accommodate 500 cups of yoghurt in one batch (A “makeshift” incubator can handle a load of 250 cups per batch)
  
−
Dissolve 0.5 kg soda lye and 1 kg yellow bar soap cut into thin slices in 12 litres of water. Boil for 2 hours and then strain. Clothes soaked overnight in a solution of this soap need no rubbing. Merely rinse them out and they will be clean and white.
+
• The duration is 3-4 hours per batch depending on the strength of the culture.
  
−
'''English bar soap'''
+
</blockquote></div>
  
−
Use 5 litres of soft water, 0.5 kg of ground (or agricultural) lime, 1.75 kg soda lye, 30g borax, 1 kg tallow, 0.7 kg pulverised rosin and 14g beeswax. First bring the water to a boil, and then gradually add the lime and soda, stirring vigorously. Add the borax, boil and stir until it is dissolved. Pour in the melted tallow in a thin stream, stirring constantly. Add the rosin and beeswax, and boil and stir until it thickens. Cool in moulds.
+
==Operations==
  
−
'''Transparent soap'''
+
<div class="booktext"><blockquote>
  
−
Any good quality white soap may be made transparent by reducing it to shavings, adding one part alcohol to 2 parts soap, and leaving the mixture in a warm place until the soap is dissolved. It may be perfumed as desired.
+
• The incubator should be sterilised before a new batch is cured.
  
−
or
+
• The incubator needs to maintain a temperature of 45°C throughout the process.
  
−
Shave 0.6 kg good quality hard yellow soap and add 0.5 litres of alcohol. Simmer it in a double boiler over a low heat until it is dissolved. Remove from the heat and add 30g of essence to give a pleasant smell.
+
• A batch would take between 3-4 hr. in the incubator. The incubation period is important for the flavour since too little or too much time will ruin the culture.
  
−
'''Bouquet soap'''
+
• It is advised to start loading from the top most tray and reach the bottom in the incubators where there is no fan. This will ensure the same flavour and the consistency of all yoghurt.
  
−
Shave 14 kg tallow soap and melt it in 2 cups water. When it is cool, add 14g essence of bergamot, 30g each of oils of cloves, sassafras and thyme. Pour it into moulds.
+
• The trays need to be cleaned after each batch.
  
−
'''Cinnamon soap'''
+
</blockquote></div>
  
−
Shave 23 kg tallow soap and melt it over a low heat in 1.2 litres water. Cool and add 200g oil of cinnamon and 30g each of essences of sassafras and bergamot. Mix and add 0.5 kg finely powdered yellow ochre. Mix well and pour into moulds.
+
==Maintenance==
  
−
'''Citron soap'''
+
<div class="booktext"><blockquote>
  
−
Mix 180g shaved soap with 300g attar of citron, 15g lemon oil, 120g attar of bergamot and 60g attar of lemon.
+
• The incubator needs to be cleaned before and after use.<br /> • Sterilisation is recommended.<br /> • The bulbs need to be checked.
  
−
</div>
+
</blockquote></div>
  
−
==Medicated soaps==
+
==Cost details==
  
 
<div class="booktext">
 
<div class="booktext">
  
−
'''Camphor soap'''
+
The incubator cost would vary depending on the type (manual or semi-automatic), the availability of materials and transportation. The cost will also differ if fabricated along with the internal fan. Plus the electricity charges also have to be considered.
  
−
Dissolve 0.5 kg hard white soap in 1 cup boiling water. Continue boiling over a low heat until the soap is the consistency of butter. Add 180g olive oil, mixed with 30g camphorated oil. Remove it from the heat and beat until an emulsion forms. This soap can be used to clean cuts and scratches.
+
Estimated cost (1998):
  
−
'''Sulphur soap'''
+
Manual Rs.15,000.00
  
−
Shave 60g soft soap and add 8g Flowers of Sulphur. Perfume and colour may be added as desired. Mix the ingredients thoroughly in earthenware bowl.
+
Semi-automatic Rs.19,000.00
−
 
 
−
'''Iodine soap'''
 
−
 
 
−
Dissolve 0.5 kg white, finely shaved soap in 90g distilled water or rose water. Add 30g tincture of iodine. Put in double boiler, melt and mix by stirring.
 
  
 
</div>
 
</div>
  
−
==More recipes for soft-soap cold process==
+
==Manufacturers==
  
 
<div class="booktext">
 
<div class="booktext">
  
−
Mix 4 kg of melted fat with 16 litres of strong lye water in a kettle. Bring it to the boil, pour into the soap barrel and thin it with weak lye water. Place the barrel in a warm place. The soap should be ready to use in a few weeks.
+
Industrial Development Board<br /> Galle Road<br /> Katubedda<br /> Moratuwa<br /> Sri Lanka
  
−
or
+
Nihal Ashoka<br /> Ashoka Industries<br /> Kirama<br /> Walgammulla<br /> Sri Lanka<br /> +94 71 7654725
  
−
Mix 5 kg clear melted fat, 3 kg soda lye and 40 litres of hot water in the soap barrel. Stir once a day and let the mixture stand until completely saponified.
+
</div>
  
−
or
+
==Further information==
  
−
Melt 4 kg fat in a kettle and bring it to the boil. In another kettle, mix 4 kg caustic soda and 0.5 kg soda in 20 litres of soft water. Pour all the ingredients together into a 200 litre barrel and fill it up with soft water. Stir daily for 3 days and then let the mixture stand until saponified.
+
<div class="booktext"><div align="left">
  
−
or
+
{| border="1" cellpadding="5"
−
 
 
−
Mix 3 kg potash, 2 kg lard and 0.2 kg powdered rosin and allow the mixture to stand for one week. Then melt it in a kettle with 10 - 15 litres of water. Pour the mixture into a 50 litre barrel and fill with soft water. Stir two or three times a day for two weeks.
 
−
 
 
−
or
 
−
 
 
−
Put 0.3 kg soda and 0.5 kg brown soap shavings into a kettle. Add 12 litres of cold water, melt over low heat and stir until dissolved. It is ready for use as soon as it is cool.
 
−
 
 
−
</div>
 
−
 
 
−
==Glossary==
 
−
{| border="1" cellpadding="5" cellspacing="0"
 
 
|- valign="top"
 
|- valign="top"
 
| valign="top" |
 
| valign="top" |
−
• Lye, Lye water, potash lye ashes
+
This technical brief was originally prepared by:
−
| valign="top" |
+
 
−
interchangeable terms for alkali made from wood soaked in water
+
Practical Action South Asia<br /> 5, Lionel Edirisinghe Mawatha<br /> Kirulapone<br /> Colombo 5<br /> Sri Lanka<br /> Tel: +94 11 2829412<br /> Fax: +94 11 2856188
−
|- valign="top"
 
−
| valign="top" |
 
−
• Potash (caustic potash)
 
−
| valign="top" |
 
−
lye water evaporated to a powder.
 
−
|- valign="top"
 
−
| valign="top" |
 
−
• Lime (or stone lime)
 
−
| valign="top" |
 
−
ground or agricultural limestone.
 
−
|- valign="top"
 
−
| valign="top" |
 
−
• Quicklime
 
−
| valign="top" |
 
−
lime that has been baked.
 
−
|- valign="top"
 
−
| valign="top" |
 
−
• Soda lye
 
−
| valign="top" |
 
−
quicklime slaked in water and heated with soda.
 
−
|- valign="top"
 
−
| valign="top" |
 
−
• Soda
 
−
| valign="top" |
 
−
hydrated sodium carbonate.
 
−
|- valign="top"
 
−
| valign="top" |
 
−
• Caustic soda
 
−
| valign="top" |
 
−
soda lye evaporated to a powder.
 
−
|- valign="top"
 
−
| valign="top" |
 
−
• Commercial lye
 
−
| valign="top" |
 
−
usually caustic soda and is the equivalent of 'lye' in most recipes.
 
 
|}
 
|}
  
−
==Equipment list==
+
</div>
−
 
 
−
<div class="booktext">
 
  
−
The following equipment is needed to make soap:<br />
+
Cathy Rich Memorial Food Processing Center<br /> Yodagama<br /> Embilipitiya<br /> Sri Lanka<br /> Tel/ Fax: +94 47 30248 and +94 77 324162 (mobile)<br /> E-mail: [mailto:crmfpc@foodhints.com crmfpc@foodhints.com]<br /> Website: http://www.foodhints.com
  
−
<blockquote>
+
The training centre was a subsidiary of Practical Action South Asia (then called ITDG) until 1997. It is now an independent NGO, but Practical Action South Asia still works closely with this centre.
  
−
1. a large iron soap kettle for making soap in commercial quantities.
+
</div>
  
−
2. a long-handled wooden ladle to stir the soap.
+
==References and further reading==
 +
'''This Howtopedia entry was derived from the Practical Action Technical Brief ''Yogurt Incubator''. <br />To look at the original document follow this link: <br />
  
−
3. a kitchen grater or a meat grinder to make soap flakes for laundry use or to grind soap for some recipes.
+
http://www.practicalaction.org/?id=technical_briefs_food_processing
 +
<div class="booktext">
  
−
4. flat wooden boxes, moulds or tubes, cut plastic bottles or plastic tubs, to mould the soap.
+
''Yoghurt Production'', Practical Action Technical Brief<br />''Preparation of Dairy Products: Agrodok No 36'', Agromisa, 1991<br />''The Manufacture of Yoghurt and Cottage Cheese'', Food Chain No 24, May 1999<br />
  
−
5. pieces of cloth to stop the soap sticking to the wooden moulds.
+
</div>
−
 
 
−
6. a plate on which to cool and test a few drops of the liquid soap.
 
−
 
 
−
</blockquote></div>
 
−
 
 
−
==Useful contacts and further information==
 
−
 
 
−
 
 
−
The following publications describe soapmaking in more detail:
 
−
 
 
−
 
 
−
*''Small-scale Soapmaking: A handbook'', by Peter Donker, IT Publishing/TCC, 1993.
 
−
*''Soap Production - Technologies Series Guide No 3,'' Centre for the Development of Enterprise, Brussels, 1994.
 
−
*''Case Study No 3: Soap Pilot Plant'', Technology Consultancy Centre, Kumasi, Ghana, 1983.
 
−
*''Soap'', Ann Bramson, Workman Publishing Co, 1975
 
−
*''The Art of Soap Making'', Merilyn Mohr, Camden House Publishing, 1979
 
−
*''Making Soaps and Candles'', Phyllis Hobson, Storey Communications Inc., 1973
 
−
 
 
−
 
 
−
Further information can be obtained from:
 
−
Technology Consultancy Centre, University of Science & Technology, Kumasi, Ghana. Fax: + 233 5160137,
 
−
 
 
−
For producers who can obtain assistance from a small business advisory service or an international development agency that has access to the Internet, there are 100+ websites on soap making. Most are either commercial sites that sell essences, oils etc that can be added to soap, or home soapmakers sites that give recipes and information on how to make soaps. The following websites have useful information and good links to other sites:
 
−
 
 
−
{| border="1" cellpadding="5" cellspacing="0"
 
−
|- valign="top"
 
−
| valign="top" |
 
−
http://www.soapbasics.co.uk
 
−
| valign="top" |
 
−
contains details of products such as essential oils and plant extracts for use in soaps, soap moulds, dyes and packaging.
 
−
|- valign="top"
 
−
| valign="top" |
 
−
http://www.sugarplum.net/tracer
 
−
| valign="top" |
 
−
has details of 'Soap Tracer' software that can be purchased to create soap recipes and calculate the amounts of oil and lye required. Also details of ingredients and equipment for soapmaking.
 
−
|- valign="top"
 
−
| valign="top" |
 
−
http://www.members.aol.com/_ht_a/oelaineo/soapmaking
 
−
| valign="top" |
 
−
Free soap recipes and instructions for beginners. Books on soapmaking for sale ('Soap Recipes', and 'Super Formulas') both by Elaine C White, details of suppliers.
 
−
|- valign="top"
 
−
| valign="top" |
 
−
http://www.amazon.com
 
−
| valign="top" |
 
−
has books on soapmaking for sale, including 'Making Trans Transparent Soap - a complete guide' (1997), and 'Making Natural Liquid Soaps' both by Catherine Failor, 'Essentially Soap' (2000) by Robert McDaniel, 'The Soapmaker's Companion - a comprehensive guide with recipes, techniques and know-how' (1997) by Susan Miller Cavitch, 'Milk-based Soaps' (1997) by Casey Makela, and 'The Handmade Soap Book' (1998) by Melinda Coss and Emma Peios,
 
−
|- valign="top"
 
−
| valign="top" |
 
−
http://www.colebrothers.com/soap
 
−
| valign="top" |
 
−
has a variety of free information, including recipes, safety considerations, ingredient suppliers, soapmaking methods and the properties of soapmaking oils, with links to many other soapmaking websites.
 
−
|- valign="top"
 
−
| valign="top" |
 
−
http://www.waltonfeed.com/old/soap
 
−
| valign="top" |
 
−
has a history of soapmaking and a free table to calculate the ratio of fat/lye for different fats and oils. There are also recipes for cold process soap and details of ingredient suppliers.
 
−
|- valign="top"
 
−
| valign="top" |
 
−
http://www.millenium-ark.net
 
−
| valign="top" |
 
−
has recipes, soapmaking instructions, a fragrance calculator and saponification chart.
 
−
|}
 
−
 
 
−
 
 
−
 
 
−
Other websites that contain details of recipes and suppliers include:
 
−
 
 
−
http://www.alcasoft.com/soapfact<br />http://www.sweetcakes.com (comprehensive list of essences and essential oils for soaps)<br />http://www.soapcrafters.com<br />http://www.ziggurat.org/soap<br />http://www.soapmaker.com<br />http://www.snowdriftfarm.com<br />http://www.rainbowmeadow.com<br />http://www.wholesalesuppliesplus.com<br />http://www.hollyhobby.com
 
  
−
'''Practical Action, The Schumacher Centre for Technology & Development'''<br />'''Bourton Hall, Bourton-on-Dunsmore, Rugby, Warwickshire CV23 9QZ, UK'''<br />'''Tel: +44 (0)1926 634400 Fax: +44 (0)1926 634401 Web: http://www.practicalaction.org'''
+
=='''Useful addresses'''==
 +
'''Practical Action'''
 +
The Schumacher Centre for Technology & Development, Bourton on Dunsmore, RUGBY, CV23 9QZ, United Kingdom.<br />
 +
'''Tel.:''' +44 (0) 1926 634400, '''Fax:''' +44 (0) 1926 634401
 +
'''e-mail:'''practicalaction@practicalaction.org.uk '''web:'''www.practicalaction.org
 +
<center>[[Image:Pa-logo-200x103.gif]]</center>
  
−
'''Intermediate Technology Development Group Ltd Patron HRH - The Prince of Wales, KG, KT, GCB'''
+
=='''Categories:'''==
 +
[[category:Example]]
 +
[[Category:Easy]]
 +
[[Category:Less than 10 US$]]
 +
[[Category:One Person]]
 +
[[Category:Global Technology]]
 +
[[Category:Food Processing]]

Revision as of 13:23, 17 August 2006

Short Description

  • Problem: Production of Yogurt, one needs to construct a yogurt incubator
  • Idea: Two methods to construct a yogurt incubator
  • Difficulty: Easy
  • Price Range: Less than 10 US$
  • Material Needeed: Water, milk
  • Geographic Area: Global
  • Competencies:
  • How Many people? One
  • How Long does it take?

Yoghurt Incubator - Manual and Semi Automatic -

PRACTICAL ACTION
Technology challenging poverty

Background

Yoghurt manufacturing is a popular small-scale food processing endeavour. Yoghurt is relatively simple to produce, can be done with a small amount of capital and there is a good demand for it in the market. According to the technical inquiries received by the Cathy Rich Memorial Food Processing Training Centre, 20% of the requests from small-scale entrepreneurs are for information on making yoghurt. The most important feature and function of this process is the incubation of the mixture since it acquires the needed flavour as this stage.

There are no small-scale industrial yoghurt incubators produced in the local market. The yoghurt incubators used by large businesses are too expensive and have a much larger capacity than is necessary for small-scale food processors (SSFP). Plus SSFPs do not have the capital or the space to accommodate an industrial sized incubator.

The SSFPs use makeshift incubators: rigifoam or wooden boxes, where the heat cannot be regulated or maintained, and do not produce good quality yoghurt. These makeshift models could only accommodate 250 cups per batch. They are also difficult to clean and are unhygienic. Therefore the SSFPs could not sell their produce and could not compete with the large scale producers.

Practical Action South Asia (then called ITDG) along with the Cathy Rich Memorial Food Processing Centre responded to a request by SSFPs to design an appropriate incubator. It has improved the standard of the yoghurt produced, it is low in cost, has a greater capacity and easy to operate and maintain.

The incubators

The yoghurt incubators developed had slight modifications to the industrial incubator. Practical Action South Asia designed two models: one which is manual and one that is semi automatic: The basic structure is the same with the difference being the thermostat unit.

The incubators introduced by Practical Action South Asia aluminium frames with rigifoam insulation. The rigifoam insulation is for heat retention which increases the efficiency and reduces the electricity consumption.

The incubator has two chambers with 6 removable shelves in each chamber. Bulbs are installed at the base of the incubator to supply the required heat.

The incubator has a glass front so that it can be judged visually when the yoghurt has matured and ready to be taken out. In the manual model, the heat source (the bulbs) have to be turned on and off as required and the incubator temperature needs to be monitored.

In the semi-automatic version, the thermostat turns off when the required temperature is reached and does not need to be monitored.

The incubator could have an internal fan which helps regulate the heat (by 4-5 degrees) but optional. If the incubator has the fan, it will increase the cost of construction, operation (electricity) and maintenance. This would keep the same flavour and consistency in all the yoghurt cups in the incubator.

In the semi-automatic incubator, the internal chambers can be sterilised easily by setting the thermostat to 100°C. This allows the production process to be more hygienic by removing any unwanted bacteria that could spoil the yoghurt or alter its taste.

The introduced yoghurt incubator has these advantages:

• The heat can be regulated
• It is insulated to minimise heat losses
• It can be easily cleaned after every batch
• It can be sterilised without dismantling
• It can be fabricated and maintained locally
• It is more efficient and durable

Technical details

Material required

Material

Specification

Quantity

Aluminium Angles

½” X ½”, 12ft lengths

03 Nos.

Aluminium Angles

¾” X ¾”, 12ft lengths

10 Nos.

Aluminium Tee Sections

1” X 1” , 12ft lengths

06 Nos.

Aluminium “U” Sections

12ft lengths

01 No.

Aluminium sheet

gauge 20 x 8" x 4"

01.5 Nos.

Welded Mesh

75 mm2

04 m2

Plain Glass

0.8 m2

Bulbs

40W

10 Nos.

Dial Type Thermometer

0°- 100°C

01 No.

Thermostat*

Wall mounted, adjustable

01 No.

Electric fan**

Low profile box fan - vertical operation

01 No.

Wires, teflon sleeving, connectors, self tapping screws etc.

As required

* The thermostat is needed for the semi-automatic model
** The fan is optional

Construction

• The incubator frame is rectangular with the glass sheeting in the front.
• The thermostat is attached to the external frame
• The size, shape and position of the trays are as shown in the drawings
• Bulbs will be placed at the base of the incubator (internally).

Specific requirements

• Electricity - 240V supply
• Floor Area - 600mm x 1225mm

Capacity

• The incubator has 2 chambers with 6 trays each and one tray hold 42

• The incubator can accommodate 500 cups of yoghurt in one batch (A “makeshift” incubator can handle a load of 250 cups per batch)

• The duration is 3-4 hours per batch depending on the strength of the culture.

Operations

• The incubator should be sterilised before a new batch is cured.

• The incubator needs to maintain a temperature of 45°C throughout the process.

• A batch would take between 3-4 hr. in the incubator. The incubation period is important for the flavour since too little or too much time will ruin the culture.

• It is advised to start loading from the top most tray and reach the bottom in the incubators where there is no fan. This will ensure the same flavour and the consistency of all yoghurt.

• The trays need to be cleaned after each batch.

Maintenance

• The incubator needs to be cleaned before and after use.
• Sterilisation is recommended.
• The bulbs need to be checked.

Cost details

The incubator cost would vary depending on the type (manual or semi-automatic), the availability of materials and transportation. The cost will also differ if fabricated along with the internal fan. Plus the electricity charges also have to be considered.

Estimated cost (1998):

Manual Rs.15,000.00

Semi-automatic Rs.19,000.00

Manufacturers

Industrial Development Board
Galle Road
Katubedda
Moratuwa
Sri Lanka

Nihal Ashoka
Ashoka Industries
Kirama
Walgammulla
Sri Lanka
+94 71 7654725

Further information

This technical brief was originally prepared by:

Practical Action South Asia
5, Lionel Edirisinghe Mawatha
Kirulapone
Colombo 5
Sri Lanka
Tel: +94 11 2829412
Fax: +94 11 2856188

Cathy Rich Memorial Food Processing Center
Yodagama
Embilipitiya
Sri Lanka
Tel/ Fax: +94 47 30248 and +94 77 324162 (mobile)
E-mail: crmfpc@foodhints.com
Website: http://www.foodhints.com

The training centre was a subsidiary of Practical Action South Asia (then called ITDG) until 1997. It is now an independent NGO, but Practical Action South Asia still works closely with this centre.

References and further reading

This Howtopedia entry was derived from the Practical Action Technical Brief Yogurt Incubator.
To look at the original document follow this link:

http://www.practicalaction.org/?id=technical_briefs_food_processing

Yoghurt Production, Practical Action Technical Brief
Preparation of Dairy Products: Agrodok No 36, Agromisa, 1991
The Manufacture of Yoghurt and Cottage Cheese, Food Chain No 24, May 1999

Useful addresses

Practical Action The Schumacher Centre for Technology & Development, Bourton on Dunsmore, RUGBY, CV23 9QZ, United Kingdom.
Tel.: +44 (0) 1926 634400, Fax: +44 (0) 1926 634401 e-mail:practicalaction@practicalaction.org.uk web:www.practicalaction.org

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