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				Making Yoghurt

						A 1 quart batch


	INGREDIENTS:

	1 cup starter yoghurt
	4 cup "dairy medium" (See below)

	3 quart pot
	wooden spoon
	wire whisk



	PRELIMINARIES:

	There are five critical aspects of making good yoghurt:

	1) Eliminating, as a preliminary procedure, any possible
	   bacterial culture than can interefere with the culturing.

	   Heating the milk-medium to almost boiling, but steaming
	   and then cooling it accomplishes the destruction of competing
	   bacteria.  It is called "scalding the milk".  In the scalding
	   process, the milk/cream *must* be brought above 140°F.

	   You must be careful, however, *not* to let the milk boil;
	   getting the milk/cream to about 170°-180°F is good.  Boiling
	   will cause some of the milk proteins to break down in such
	   a way as to cause the resulting yoghurt to loose its smoothness,
	   just as will happen to overheated chocolate.

	   The yoghurt will be sort of grainy - not what you want.
	   After chilling the yoghurt, an overheating of the milk will
	   also display a separation of a greenish slightly opaque
	   liquid in your finished yoghurt - a telltale sign that all has
	   not gone well.

	2) Maintaining the proper ambient temperature of the developing
	   culture between 110° and 120° Farenheit.  Few things or
	   places provide a stable and correct temperature as well as an
	   electric yoghurt maker.  Anything greater than 120° will kill
	   the bacterial culture, yielding some unpalatable glop instead
	   of yoghurt.  If the temperature is too low, it will leave
	   our Lactobacillus collection nonfunctional, and again,
	   glop is the result.

	   Salton happens to make a simple and inexpensive electrical
           device that works very well.  It makes a quart at a time.

	3) Selecting the processing time to determine the sweet-tangy
	   property of the yoghurt: 8 hrs. for a smooth-sweet taste, to
	   12 hrs. for a tangy taste.

	4) Selecting the culturing medium to determine the thickness
	   and richness of the yoghurt.

 	   Any standard milk form will do, and any combination of
	   these will also work:
 
		a) skimmed milk
		b) 2% milk
		c) regular "whole" milk
		d) real "whole" milk (from the udder, so to speak)
		e) nonfat dried milk (reconstituted if used alone)
		   Carnation is the best brand I know of for this.
		f) evaporated milk
		g) heavy cream

	   The richness will depend on the amount of butter fat; the
	   thickness will depend on the content of both butter fat and
	   of protein.  Evaporated milk increases both.

	   If you use all heavy cream, you'll wind up with a wonderful
	   substance very much resembling sour cream, most like old
	   Breakstone's if you limit processing time to 8 hrs.
	   It will have an additional rich undertone, however.
	   Half and half (milk and heavy cream) makes a yoghurt that
	   goes very well with ripe fruits.

	   The lighter you go up the scale, the more delicate the
	   result; the more delicate the result, the more it will tend
	   to "weep", or discard and pool its own water content in
	   an acidic whey.

	   A nice thick yoghurt for those not into fat (although why,
	   I can't imagine :-) is a milk or skimmed milk with additional
	   nonfat dried milk.  This increases the protein, without
	   increasing the fat content.

	   I haven't tried using condensed milk which is basically
	   evaporated milk plus sugar.  Instinct says this is probably
	   not a good idea since any remnant of yeast will cause a
	   riot of fermentation - but ..., if you are careful in
	   the scalding. you should have a fairly clean bacterial
	   slate with which to start your bacterial culture of
	   Lactobacillus acidophilus and friends.  These bacteria
	   (anærobic) make yogurt by gobbling up the milk sugar,
	   lactose (and others) and turn lactose into lactic acid.

	   This is why people with genetic lactose intolerance can
	   eat yoghurt with no problem.

	   The increasingly acidic environment curdles the milk
	   proteins.

	5) Selecting the bacteria of the culture, i.e. selecting
	   your starter culture; you can use a prior portion (about
	   one cup), a small container of a commercial yoghurt
	   and/or capsules of "acidophilus" (the essential bacterium
	   in question) available at drug stores and health food stores.

	   L. Acidophilus bacterium (liking an acidic environment)
	   comes in a variety of strains, and the preferred strain
	   for yoghurt is "acidophilus bulgaricus".  Dannon happens
	   to contain this strain.  You can also buy it explicitly
	   in drug stores.  Commercially, the best cooking yoghurt
	   I've found is the brand Columbo, but I happen not to
	   remember whether it contains live bacteria (this is
	   essential) or whether the strain is bulgaricus.  The best
	   all around commercial eating yoghurt is Continental. 
	   Like many Eastern yoghurts, this is thickened by draining
	   off a good amount of its whey.  You can do the same by
	   hanging yoghurt in a tied up sheet of muslin for several
	   hours.  Several layers of culinary grade cheese cloth can
	   do the same thing.

	   Do pay attention to the sale date on any commercial yoghurt
	   that you may use as a starter; while the yoghurt may be
	   perfectly good to eat, it may have either developed a yeast
	   (fermenting bacterium), or the culture may be sufficiently
	   weakened so as not to produce a good yoghurt.  It may also
	   have developed fungal spores.  We are actually surrounded
	   with bacteria and fungal spores; they were here long before
	   we were.

	   Buy freshest yoghurt, and use it as your starter within a
	   day or two.

	   Similarly, if you intend to use a portion of your last batch
	   as a starter, don't let it linger in the fridge for a month,
	   although you might get away nicely with three weeks - or even
	   a month.  A week, is a good rule of thumb.
	

	METHOD:

	0) Plug in the yoghurt maker, and put the cover on it, to heat
	   to the proper bacterial breeding temperature.

	1) Heat the selected mixture (1 quart) in your preferred way
	   to the point where it is just about to boil; the transition
	   to actually boiling can happen very fast, so pay close
	   attention.  If on a stove, stir continuously.

	2) Remove from the heat immediately.  You can either let the
	   mixture cool naturally or help it along with an ice or cold
	   water bath; it that last case, it will cool quickly (keep
	   stirring), so pay attention.

	   Use a candy thermometer.  In time, with experience, the light
	   dipping of a clean finger into the cooling mixture will tell
	   you when the 110°-120° F temperature range has been reached,
	   if you do this often enough.

	3) Now add your starter mixture, and mix thoroughly, not
	   violently, i.e., use a wisk, not an electric hand mixer.
	   If you mix too violently you can destroy the texture again,
	   for several long winded reasons that I won't elaborate on
	   here, except to say that it involves breaking protein
	   hydrogen bonds.

	   But, don't leave lumps; the object is to distribute the
	   living culture in the mixture.

	4) Pour the mixture into the yogurt maker's container; put
	   its cover on; put the container into the preheated yoghurt
	   maker, and put its cover on.

	5) Note the time and when your selected 8-12 hours is up.

	6) Check at the appointed time; if the mixture is not geled,
	   either the culture was too weak or you didn't add enough of it.
	   You may be able rescue by letting the processing continue for
	   another hour.

	7) Assuming that you have a well solidified yoghurt, refrigerate
	   it immediately in the maker's container.

	8) Not a bad idea is to purchase an additional container and
	   top, so that batches may overlap.  For some people, buying
	   several of these might be helpful.

	   Yoghurt is one of the world's most versatile foods. It is used
	   ubiquitously in middle eastern and Greek cooking, as well as
	   Indian, Georgian and Mongolian cooking.  Homemade, in this way
	   is far superior to what is available commercially, which often
	   contain pectin and gelatin (animal products) as thickeners.

	   Try an especially thick batch of homemade yoghurt with fresh
	   fruit.

	9) While Yoghurt is ubiquitous in Indian cuisine, they have
	   another way of making "curd", that goes to the heart of
	   this complicated biological process.

	   To make the "cheese" called Paneer.  The milk mixture is
	   first scalded as for yoghurt, then an acid of sort is added:
	   lemon or lime juice, vinegar, citric acid, .... The curdling
	   is almost instantanious.  Draining the curd of the whey by
	   muslin gives two culinary items.  Notice, however, that the
	   lactose is not converted to lactic acid, so yoghurt and
	   paneer curds are quite different.



	FURTHER REFERENCES AND MORE SPECIFICS:

	Yogurt [Wikipedia]
	Lactobacillus [Wikipedia]
	Lactobacillus Acidophilus [Wikipedia]
	Lactobacillus Delbrueckeii subsp. Bulgaricus [Wikipedia]

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