[Bilsch]

Refrigeration only came in in the middle of the 20th century so most beer historically has not had fermentation control.  Not saying it's a bad idea but just not pertinent to this topic.

Mechanical refrigeration came in the early 20th but before that there were a lot of holes dug in the ground and uncounted tons of ice used to control beer fermentation and lager temperatures. So I have to take issue with your assertion that most beer historically has not had temperature control.

[Robert]

Mechanical refrigeration actually began in the 18th century,  but was fully developed in its modern form in the 19th century by Carl von Linde, specifically for the brewing industry.  Bilsch is right.  Brewers always had temperature control.  Deep cellars, tons of ice, and failing that, prohibitions against brewing when temperature could not be held low enough by these means.  So brewing was historically a limited, seasonal activity, and mechanical refrigeration simply allowed us to brew year round. Thus temperature control has always been paramount in brewing. And if you are enjoying air conditioning or fresh food from your fridge, thank a brewer.

[hopfenundmalz]

Mechanical refrigeration actually began in the 18th century,  but was fully developed in its modern form in the 19th century by Carl von Linde, specifically for the brewing industry.  Bilsch is right.  Brewers always had temperature control.  Deep cellars, tons of ice, and failing that, prohibitions against brewing when temperature could not be held low enough by these means.  So brewing was historically a limited, seasonal activity, and mechanical refrigeration simply allowed us to brew year round. Thus temperature control has always been paramount in brewing. And if you are enjoying air conditioning or fresh food from your fridge, thank a brewer.

Hey, I was going to bring up Carl von Linde. The first commercial application of mechanical refrigeration was at the Spaten Brewery in 1873.

Block ice was cut from lakes and rivers to store and lager beer before refrigeration. The brewing museum in Bamberg is in an old brewery. There is a large room in the cellar that was lined with ice to keep the beer cold.

I have been in one cellar in Bavaria that is naturally at 3 to 3.5 C year round, not bad for lagering temps.

[Robert]

That is nice and cool.  Deep down, temperatures will hold steady year round at about the average annual surface temperature, of course.  I recall that at Burton on Trent, they cleverly took advantage of this to control fermentation temperature by running water from deep wells through piping inside the fermenters, bringing deep cellar temperatures to any desired location.  Maybe the first applied geothermal technology? So many advances came from brewing.