diacetyl rest for ale yeast

[jsvoboda]

What benefit does dropping an ale yeast down to 50 degrees have on the beer. Assuming that the beer has been fully attenuated and the yeast strain is a low diacetyl producer in the first place, why do it?

[dick murton]

50 sounds rather low for a diacetyl rest. 15 to 18 deg C (whatever that is in deg F) is generally a more typical temperature. 50 sounds more like a temperature used for lagers towards the end of fermentation, when the temperature is allowed to increase - a sort of diacetyl rest. Not all lagers of course have this sort of rest.

If you are able to cool the beer down very rapidly, then a short rest may help the yeast to settle out without suffering too much shock, leading to cell damage, autolysis and off flavours / hazes etc.

Other than that.... But of course flavours do change over time, and at different temperatures. Perhaps the key is to taste the two beers, one fermented with a rest, one without. Make sure the bulk of the yeast is taken off as soon as possible to pervent autolysis though.

Have fun tasting. Cheers