From touring Miller & Budweiser breweries, I noticed both sites have caves – which have steady year-round temperatures. I assume the caves were used to lager, which means “storage” in German.  Lager yeasts, unlike ale yeast which ferment at room temperature, do their primary fermentation in the mid-50 degree range.  During secondary fermentation the temperature is dropped steadily to slowly deactivate the yeasts.  Back in the day, the barrels could be moved deeper into the cave day-by-day to slowly lower the temperature from the mid-50s down to almost freezing (35°F).

Yogurt Maker?

I had an idea to automate this process using an Arduino, especially after reading Chris Reilly’s Arduino yogurt maker from Make Magazine volume 25.  Everything I’ve done here was based on that, so I’ll assume you’ve read it.

Lagering is essentially the same process except instead of using a heat source (crock-pot), we use a cooler (refrigerator).  Getting the refrigerator to maintain temps above 40°F can be tricky, so normally an external temperature regulator is used.  But this requires me going out to the fridge every day to lower the temperature by one degree.  So why not automate it?  Laziness FTW!
Continue reading