Cool fermentation

[rpt]

I started my Woodforde's Wherry last Thursday and initially there was plenty of activity from the airlock but for the past 3 or 4 days all is quiet. It's a bit cooler in the room than it was (about 16C instead of 18C) so I'm thinking the fermentation may have slowed right down or stopped. I will take a hydrometer reading tonight but I just want to know whether it matters if it is this cool - I will just need to leave it longer to ferment out. I know temperatures above 24C are meant to cause bad tastes but do low temperatures?

 

[andyd]

A low temperature shouldn't cause you any taste issues. The main risk is that fermentation will slow down or even stop. Your plan to take a hydrometer reading is the right one. It may be that fermentation is finished (an SG of 1012 ish I guess) but if it's much higher then I suggest you move it somewhere warmer if you can, or wrap it in blankets etc. Maybe give it a gentle stir too to encourage the yeast to keep going.

 

[graysalchemy]

Cooler temps may cause a lower ester production by the yeast, but wether you will be able detect this I don't know. I know that I brewed my house bitter at 18c instead of the normal 21c and it certainly was not as fruity as it normally was which to me was detrimental to the flavour of the beer. :thumb:

 

[Ceejay]

Also depends on the yeast you're using. I've got an APA fermenting on US-05 at the moment at 14.5C (58F). It's going slow but there's a good half inch krausen (which is about as much as I get with US-05). With English ale yeasts, you probably want to be around 21 - 23C I reckon.

 

[rpt]

Gravity last night was 1020 so it's made a good start from its OG of 1042 but seems to have stopped. I will try it to warm it up - I think the FV needs a warm bath.