It was a tradition in the UK, too. Agricultural labourers expected to be served beer during the harvest as part of their wages. Harvesting was reckoned to be impossible without sufficient supplies of beer.
In the UK, Harvest Ale was usually a form of Mild Ale but, and here’s the important bit, weaker. So when X Ale averaged around 5% ABV, Harvest Ale was more like 4% ABV. You wouldn’t want something strong enough to incapacitate your workers.
The Erntebier in Saxony was rather different, being stronger than the standard beer it was based on. How odd.
Here’s my paraphrasing of Olberg again.
In many regions, but especially in Saxony, Erntebier is brewed.
It’s a Braunbier which is usually brewed top-fermenting, except while Braubier and Weissbier in the region is usually brewed to a gravity of 8 to 8.5º Balling, Erntebier has an OG of 9.5 to 10º and must also be lagered longer. It’s also more heavily hopped than Braunbier, at a rate of 1.2 kg. per 50 kg. of malt.
When primary fermentation has finished, the casks are washed and kept completely filled and sealed by hand with wooden bungs, without using a hammer. Through this the beer gets some life and is liked by the harvesters because it tastes powerful and has particular thirst-quenching properties. For a further description see the chapter “Braunbier”
Source: Olberg, Johannes (1927) Erntebier in Moderne Braumethoden, pp 68, A. Hartleben, Wien & Leipzig.
So just like Saxon Braunbier, except a little stronger and a little hoppier. Funnily enough, a beer of 9.5 to 10º Plato is about exactly the same strength as pre-WW I British Harvest Ale. The hopping rate, which is the equivalent of 8lbs per quarter of malt, is pretty much the same, too.
Here are a couple of modern German Erntebiers, both from Bavaria. Note that the one from Grosch is, at under 3% ABV, pretty weak.
|Modern German Erntebier|
|2014||Arnsteiner Brauerei||Seinsheim||Ernte Hell||1044.44||1008||4.80||82.90%|
|2014||Braugasthof Grosch||Rödental||Grosch Erntebier||1031.23||1010||2.80||69.26%|
|Arnsteiner Brauerei website|