YOGURT MAKING: TWO QUARTS
David B. Fankhauser, PhD
Professor of Biology and Chemistry
University of Cincinnati Clermont College
Batavia OH 45103
This page has been accessed
times since 3 Sept
2002.
~1980, rev. 17 December 1993, 5 Dec
98,
11 Dec 98, 18 Apr 99, 20 Apr 99
(See my
main yogurt page for illustrated steps to make four quarts
of yogurt.)
Yogurt is a fermented milk product in which
a mixed
culture of
Lactobacillus bulgaricus
(or occasionally L. acidophilus) and Streptococcus
thermophilus which produce lactic acid during
fermentation. This lowers the pH and makes it tart. The partial
digestion of the milk when these bacteria ferment milk makes yogurt
easily digestible.
In addition, these bacteria will help settle GI upset including
that which follows oral antibiotic therapy by replenishing
non-pathogenic flora of the gastrointestinal tract.
Several factors are crucial for successful yogurt making:
- a. good sterile technique (i.e., proper cleansing
and heat treatment of glassware)
- b. proper incubation temperature. Lactobacillus
is killed if exposed to temperatures over 55oC, and does not
grow well below 37oC.
We will use a temperature on the high side of its preferred growth
temperature so that most pathogens will be strongly inhibited from
growing.
- c. protection of the starter from contamination.
Do not open the starter (either Dannon Plain yogurt, or 4 oz starter
from
the previous yogurt batch) until you are ready to make the next batch.
Yogurt is preserved by its acidity which inhibits
the
growth of spoilage bacteria. With lids intact, this yogurt will keep at
least a month or two in the refrigerator. After that time, a layer of
non-pathogenic white mold may form on the top. After this is removed,
the yogurt is still suitable for cooking.
Baked goods will rise well when yogurt is used due its acidity.
Use it as part or all of the liquid in cakes, waffles, pancakes and
muffins, and cut down on the amount of baking powder.
Yogurt is an excellent dish by itself, but is valuable in its
many other uses
Ingredients:
½ gallon milk
½ cup Dannon plain yogurt (use a fresh culture for starter)
Apparatus:
double boiler (or heavy pot) with lid, capacity 2 ½ qt
two qt. bottles with lids, sterilized in boiling water
an 8 oz jar with lid, very clean and sterile.
candy thermometer, reading range = 40 to 90oC (100 to 200
oF)
1 Styrofoam cooler
- Heat milk to 85-90oC in double
boiler (185-195 oF). If using a heavy pot, stir frequently
to prevent sticking. Keep covered.
- Remove from fire, place covered pot in pan
of clean cool water until stirred milk is very close to 55oC
(130oF).
- Stir up yogurt starter with a clean fork,
add to 55o C milk, stir thoroughly, (temp should drop to 50
oC (122 o F) or just below). Pour still warm mixture
into
the three bottles, plus the smaller 8 oz jar. Cover immediately with
the
sterile lids.
- Place filled bottles in cooler, add enough
50oC (122 oF) water so that bottles are
surrounded,
but the water is well below the lid rims. The starter jar will have to
be placed on a support to keep its lid above the water.
- Do not disturb
the yogurt and it will be finished in 3 hrs, provided the temperature
does
not drop below 40 oC (104 oF).
- Refrigerate until needed.
For more firm yogurt, add 2 Tbl powdered milk to the ½ gallon of
milk prior to heating. Either whole or skimmed milk may be used, but
whole milk makes richer yogurt.
YOGURT HAS MANY USES:
My favorite uses of yogurt include:
1) In place of sour cream. Add dollops:
to baked potatoes,
on rice dishes,
on bowls of soup (especially lamb stew, chilli or
borscht).
with hot chili (works as a fire extinguisher too!)
2) In cucumber-yogurt soup (fabulous summer dish)
3) As a liquid in soda-raised breads,
waffles and pancakes
4) To
make Laban , a Lebanese soft cheese, (easy yogurt cheese) can be
made by hanging yogurt in a clean cloth, permitting the whey to drip
into a bowl. Add salt to taste. It is delicious served with pulverized
spearmint and olive oil as a dip.
5) as a starter for cheese
6) as a starter for yogurt (see above for how to do this)
7) Diluted and slightly salted to make ayran (EYE-ron), a
refreshing
Turkish cool drink.
Check any Middle Eastern cookbook for a variety of uses.