Yogurt “Cooked” in a Cooler

By Bill Palladino

Last month you heard me bemoaning the lack of local proteins available for purchase in northwest Michigan.  I neglected to say that one easy protein source is dairy, and we happen to have a few great producers around here.  Yogurt is a daily part of my diet, so I thought I’d toss this your way.

This is my recipe for making your own yogurt without any type of appliance.  No oven on low.  No yogurt maker.  No need to leave your experiment on the backseat of your car in July Sun, etc.  I try to make this once a week or so.   This particular recipe makes a lot of yogurt.  I use a half-gallon of Shetler’s whole or 2% milk.  (Shetler’s is a regional dairy here in northwest Michigan, based in Kalkaska.)  This half-gallon will fill 8 one cup Pyrex containers, and a 32 oz. yogurt container.  Now I know the math doesn’t work out, but that’s because I add a few ingredients other than milk, and don’t fill the containers up all the way.


Time needed:
About 1 Hour

What you’ll need:


  • 1/4 cup water
  • 2 quarts (8 cups) whole milk
  • 6 tablespoons sugar (I use organice cane sugar.)
  • 1 vanilla bean, seeds scrapped from 1 pod (optional)*
  • 1 tablespoon vanilla extract
  • 2 yogurt starter packets (or one small container of existing yogurt with active cultures, thought this takes some practice to get consisten results.) I use a product called YoGourmet. It comes in dried form, ten packets to a box.

*Good, fresh, vanilla beans can be very expensive. Double-check the price before throwing them in your cart.


  • 1 – 2 quart or larger pot, preferably with thick bottom
  • 1 – instant-read thermometer
  • 1 – large stainless steel bowl
  • Ice
  • 12 – small (1 cup) glass containers with lids (or three large 32 oz. yogurt containers) or a combination
  • 2 – 32 oz poly water bottles with tight-fitting lids
  • 1 – beach cooler
  • towels


Sterilize everything the milk and yogurt will come into contact with.  I have good luck just passing it all through a “sanitary” cycle of my dishwasher.

Put the 1/4 cup of water in the pot, with heat on high, and get it boiling. Turn the heat down to medium, then slowly add all the milk.  I find this method helps to keep the milk from scorching.  Stir the pot constantly, keeping the burner on medium.  Don’t be tempted to turn it up high. You’ll only make a mess of things.  Use the thermometer to check the temp.

Once the milk starts getitng warm, you can slowly add in the sugar and vanilla, making sure both are mixed well.

You’ll want to get the mixture close to its boiling point which is pretty close to that of water, at 100 degrees centigrade, or 212 degrees farenheit (at sea level).  More importantly, you’re looking for a sustained temp over 180 degrees F.  This is where most bacteria die off.  Unlike water, milk will start to substantially change its look in the pan when it gets close to this temp.  It’ll dance around, and make some tight bubbles, appearing to “soften” or get lighter in the pan.  (Milk also has a nasty tendency to scald under high temperatures, and you’ll want to skim any coagulants off the milk as they appear.)

YogurtWhen your mixture begins to boil (or is at least 180 degrees F for one minute), take it off the heat and begin to cool the pan. I use a stainless steel bowl large enough to hold the pot and filled with ice. I place the hot pan into the stainless bowl right on top of the ice.   Put the thermometer in the pan and gently mix the mixture while it cools.  This will take about five to ten minutes.

In the meantime, boil two quarts of water in a pot or tea kettle, and fill the two water bottles.  Then seal them tight.

Prepare your two packets of yogurt starter by cutting the openings.  When the mixture reaches a temperature of 112 degrees get ready to add the starter culture.  (The culture has a fairly narrow range in which it thrives, between 108 and 112 degrees F.)  You must add the culture while the mixture is in this temperature zone.

YogurtNow working fast to preserve the heat of the mixture, pour the mixture into each container and put the lids on tightly.  Carefully place the containers atop one another and distributed around inside the cooler.  Place the two water bottles inside the cooler.  These will be your heat source for the 8 hour cooking cycle.  I either lay them atop the yogurt containers or centered within the cooler.  Place a towel or two over all the containers inside the cooler, close the cooler tight, and you’re done.  Just find a nice cozy spot for the cooler to rest overnight.  Or for at least 8 hours. (You’ll be happy to know this particular cooler I got as a door prize at an education conference in Texas.)

The longer you leave the cooler unopened the firmer your final product will be.  I often leave mine for 12 hours.  When you’re satisfied that they are done, pop them all in the refridgerator.  They are ready to eat as soon as they’ve cooled down.

I use almost the same recipe for making kefir, except that the temperature zone for kefir culture is substantially lower than for yogurt.