Archaeologists have discovered a "refrigerator" among the houses surrounding the German Stonehenge. Ringheiligtum Pömmelte was originally built by Beakers and continued without break into the Aunjetitzer or Unetice Culture. The refrigerator (big pot in a deep shaft) was probably from this second phase. (I believe it is clear that the shaft is not a well)
(This is an aerial video of the enclosure, first of a series)
The news of this discovery stirred some lingering questions I've had about the Beaker homestead and daily life, being that it was a dairy culture and the logistical problems of food preservation. As Victor Mair mentions in his blog post "Galatic Glimmers", fermentation of milk into something like kumis is likely how steppe peoples and Beakers would have partaken. Since Steppe folks were seasonal movers, refrigeration in wells or pits may not have been a worthwhile effort. Plus, lactase persistence appears to have been much less common than in modern Europeans, so fermentation must have played a big role in consumption.
As these people intermingled and settled in Northern Europe and around the snow-capped mountains further south, keeping raw milk products for longer periods of time became viable. With that, the need to process milk may have been reduced while changing consumption habits.
So as a background, it may be surprising to know that refrigeration has been around for quite awhile. In this case, quite a while. There's about three methods ancient people used to refrigerate food or keep ice. Evaporative cooling has been around since at least the Bronze Age (Yakhchals, Zeer Pots, Chinese Jian fridge). Unsurprisingly, this method is more conducive to warm climates where evaporation is faster.
As a side funny, See Jian's high-tech $14,000 fridge:
Subterranean spaces and heavily-insulated ice rooms seem to have worked in much of Europe where the climate is cool enough. In fact, there are other examples of cold storage from Beaker arrangements in Europe, such as these 'larders' of Oban, Argyll. (and later discoveries Swiss pits, Pass-me-a-cold-one)
Cooling milk, yoghurt or beer may have been as simple as chilling pots in lake water or a well.
A lot of European food was preserved by smoking, salting, brining/pickling and fermenting. At least in the Isles and Far North of Europe, preserving butter was done in bogs, which sounds gross but actually produces good results. So good, that a lot of these Bronze Age butters are still being found, some from the Beaker period.
Refrigeration techniques shouldn't be too surprising, but how common was it, and how might have it changed milk consumption?