Finer Points To Thicker Yogurt
The ingredients for yogurt are simple enough, milk and starter. And, thanks to the Instant Pot, the milk incubates at a consistent temperature for between eight and twenty four hours making our part simple too. Why then can the results be wildly unpredictable? The few steps prior to the Instant Pot are key; also simple, but imprecise. This is where attention and patience and mindfulness enter. This is where we are humbled by working with a live organism, bacteria. And, this is the art of cooking, where we are interacting with nature and becoming part of the process.
Here is my experience about preparing the milk for the Instant Pot. You can read the first post with the recipe here. Instant Pot Yogurt Pure and Simple
Use yogurt starter at room temperature. I had been doing this intuitively all along as logically cold starter will cool the warm milk so carefully brought to 115 degrees F. Indeed, Sandor Katz confirms this in Chapter 7 of The Art of Fermentation.
Yogurt starter is simply two ( or up to four ) tablespoons of a yogurt brand you like that is plain and indicates on the label ‘active yogurt cultures’. You can also use yogurt made from a prior batch.
For thick yogurt, the milk must come to a full rolling boil. It must “bloom” in my experience, meaning boiling to the point of ballooning up and forming a dome. Use a large pot such that a half gallon of milk only fills it half way. This allows plenty of space for the rolling boil to fully “bloom” without milk boiling over. Heat the milk at a high enough heat to boil, not distracting your attention. This takes patience and restraint from doing something else. The amount of time will depend on your cooktop. Watch little bubbles form under the surface. It may seem like it will never fully boil. As the number of bubbles multiplies with vigor, covering the surface, a rolling boil will soon occur. When the surface begins to ballon and the milk is headed to boiling over, take the pan off the heat source immediately. Let the “bloom” subside and then pour the milk directly into a heat proof or stainless steel bowl to begin the cooling process. This rolling boil with “bloom” I have found is what produces thick yogurt in an Instant Pot.
To speed up the cooling process cool the bowl of milk in a bed of ice. A larger bowl with a bit of ice at the bottom is just enough to speed things up but this is not necessary. Regularly check the temperature with a thermometer. Over ice, the milk will take about 15 minutes to cool to 115 degrees F.
The milk at 120 degrees F. will quickly cool to the ideal temperature of 115 degrees F. Test a drop on your wrist. It should be the temperature just right for a baby’s bottle. If the milk is too hot it can kill the live bacteria. Add 1/2 cup milk to 2 TBSP yogurt starter and gently whisk. Transfer the bowl of warm milk to the Instant Pot insert and then whisk in the milk/starter mixture. Clamp the lid, press ‘yogurt’ and that’s it. The Instant Pot ‘yogurt’ setting is defaulted to 8 hours, but this may be increased by pressing the plus sign.
With patience, mindfulness and practice making your own yogurt is simple and a delightful ritual.
