Ingredients
| 4L | Milk (2 or 3.2%) |
| 1 cup | Buttermilk (see NOTES) |
Recipe
- Pour milk into InstantPot1, add buttermilk, and set the yoghurt program to “Less” and time to 8 hours.
- Wait for the fermentation to complete (milk will be sour and it will thicken). It will likely take quite a bit more than 8 hours, but it is not necessary to extend the program time. The InstantPot will keep milk relatively warm as it is well insulated.
- You can use immersion blender to make the sour milk more smooth, especially if it started to separate whey. It will result in creamier cheese.
- Turn the InstantPot to Saute and set time for 9 minutes. This is my Normal setting. Occasionally, stir the contents gently to distribute the temperature evenly, but try not to break any curds that already formed.
- Once you can see that clear whey separates from the curds, take the pot out of the InstantPot and set it aside to cool to room temperature. It is important for keeping milk fat in the cheese rather than draining with the whey.
See the two videos at the bottom of this post. The first shows how the mixture looks at the start, and the second when it is complete. Note the clear whey between the curds. It is important to not overheat the mixture or the cheese will become grainy and floury instead of creamy and smooth. - Drain the cheese through cheesecloth on a colander or large sieve. Once most of th whey has drained, lift the corners of the cheesecloth and tie them together with a string. Hang the sack formed, over a pot to collect the dripping whey (I use a knob of one of the over-the counter cabinets to do so. See Fig.1.
- Once the whey stops dripping completely your cheese is ready.
- You can press more whey out of the cheese by placing the sack in a colander, putting a plate over it, and adding a weight at the top (a big jar filled with water will work for that). That way you can obtain firmer cheese suitable for pierogi or crepe filling, or even for cheesecake.
Footnotes
- I use InstantPot to ferment milk and then to process it to make curds. My InstantPot has three setting: Less, Normal, and More (Boil) for making yoghurt; the lowest keeps the temperature at about 32-34°C which makes the fermentation much faster than at room temperature and is close to optimum for sour milk bacteria. You can ferment milk at room temperature, but in such case I suggest to warm the milk to about 35°C before adding buttermilk, and keep it in the warmest place, like near a stove. This will speed up the process, but you may still need a couple of days to complete the fermentation. You can process the sour milk on stove top, instead of in InstantPot. Use medium high heat, just until the clear whey separates. ↩︎
NOTES
When I lived in Poland, you could leave your milk on the counter top in the kitchen for a day or two and it would turn sour. The milk was pasteurized, but still had enough of lactic acid bacteria to ferment. Also, it was possible to get milk “straight from a cow” from a neighbour farmer when you were at the cottage.
In Canada where I live now, and also in the States, milk is completely sterilized, and if you leave it on the counter top for long enough it will often turn bitter and gelatinous and completely unpalatable. You also cannot legally get milk “straight from a cow” unless it is your own cow.
What this means is that you need to add bacterial culture to the milk. The particular bacteria that makes sour milk is Lactobacillus acidophilus, which is commercially used in food industry for fermenting milk and produce some probiotic dairy products. Probiotic yoghurt is produced using a different bacteria, Streptococcus thermophilus and Lactobacillus bulgaricus, which thrive at higher temperatures (40-44°C) than Lactobacillus acidophilus (~37°C). I never tried to make cottage cheese from yoghurt, but it probably can be done.
In short, you can add a dairy product containing active bacterial culture to milk, and initiate fermentation this way. The product I use is known in Canada as buttermilk, and two brands available in Ontario that worked for me are Neilson and Hewitt. Some other brands, even though they listed bacterial culture did not work. Your best approach is to try it on small batches, and go to full scale once you confirm what works. In Greater Toronto Area, Polish stores Starsky recently started selling zsiadłe mleko (sour milk); I tried it and it worked too.
In Poland it was possible to buy tablets with sour milk bacterial culture; I don’t know if it still is the case, but I didn’t find them in Greater Toronto Area.
Videos
If the video plays automatically at low resolution you can manually adjust it to HD. Best viewed in Full-Screen mode.
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