In the old days Quark used to be made by letting milk sit. It would turn thick and sour by itself. Today it is impossible because the milk has been pasteurized and will just turn bad. If
you have access to unprocessed milk, than you can still do it the old fashioned way. But be aware, that the milk might be contaminated by other bacteria. The safest way is to buy processed milk and inoculate
it. Inoculation is nothing else but putting the right bacteria to the milk. You can either buy the bacteria or start you own culture.
Here a little bit to pasteurization:
It is named after
Louis Pasteur, who lived from 1822 to 1895 in France. He found out that certain microorganisms will cause fermentation. He later discovered that if he heats milk to 160-165 F (71-74 C) and holds the
temperature for 30 to 40 seconds, that the milk will stay good longer. This is based on the killing of all bacteria in the milk. It is sadly to say that also the "good" bacteria has been
killed. Now all milk you buy in the store has been pasteurized. Here is a little hint: If your milk is close to expire, just pasteurize it again and you can keep it for additional 3 days.
The beginning of all
cheeses is a soft cheese called Quark in Germany, which is nothing but thickened milk. This thickening is caused by acidification (fermentation) with the help of milkbacteria. In this fermentation process
the milkbacteria converts the lactose (milksugar) into lactic acid (milk acid). Since store bought milk has been pasteurized, and all bacteria has been killed, we need to put the right bacteria back into the milk
by inoculating it with a starter culture.
When making you own starter culture, you have 3 choices:
Using yogurt, buttermilk, or rennet (enzyme). We will focus on yogurt and buttermilk only.
Yogurt is thermophilic, that means that the bacteria likes it very warm. The bacteria name is Lactobacillus bulgaricus and Streptococcus thermophilus. Temperatures around 97-108 F
(36-42 C). As a result a Quark substitute will be made much faster, but it will taste a little bit more sour, and you have to watch for the temperature. You can used thermos bottles or a yogurt maker to assure the right temperature.
I would not recommend to do it on the stove or in the oven, because temperature may vary and kill the bacteria.
Buttermilk is mesophilic, that means that the bacteria likes it warm. The
bacteria name is Streptococcus cremoris. Temperatures around 65-90 F (18-32 C). As a result Quark-making takes longer, but it will taste less sour, and you can make it at room temperature. Buttermilk is used in Germany
for Quark production. Quark made with buttermilk is also suited for baking in the form of Schichtkäse (a dryer form of Quark).
Important tips to follow:
- Buy the freshest products you can get.
- Do not use yogurt thickened with gelatin, because it just will not work. Most fat free yogurts contain gelatin. You might have to go to a health food store.
- Do not buy skim milk or ultra-high pasteurized milk (the kind you can store on the shelf).
- Use 2% or 4% milk only. Than higher the percentage, than creamier it will be.
- Rinse all equipment (including cheesecloth) with boiling water. This reduces the risk of infection with other organisms.
Enjoy your Quark or cheese making.