Fermentation temperature difference

[mr_jolly]

I'm hoping to get my first AG brew underway next weekend but before I do I want to work out where's the best place in my house for fermenting. To help me decide I'd planned on putting a few vessels of water in various parts of the house and monitoring the temperature (morning, afternoon, and late evening) to work out where would be the best place to get a steady fermentation temperature (approx 20 degrees C).

The only question I have is will my water vessels be the same temperature as the fermenting beer? or will the fermentation process boost the heat of the water? If it does tend to boost the heat does anyone have a figure of exactly how much?

Many thanks

[196osh]

Heat is a byproduct of fermentation, yes.

I have heard figures of around 2C, but that could be wrong.

[mr_jolly]

Thanks for your response. I'll aim for 18 degrees for my water then (shouldn't be too hard with the weather being as dire as it has been!). Still I can hopefully forget about the weather in 9 weeks or so (depending on how long I can hold off drinking it!)

[grmills]

And if it starts overheating don't under-estimate the effectiveness of draping a wet towel over the fermentation bucket lid. All that water evaporating off can pull several degrees out if you keep it damp.

[mr_jolly]

And if it starts overheating don't under-estimate the effectiveness of draping a wet towel over the fermentation bucket lid. All that water evaporating off can pull several degrees out if you keep it damp.

I considered wrapping a damp/wet towel (or similar) around the side of the FV but is putting one over the lid enough? The only problem I have with wrapping around the side is the drips (I don't think I have anything that's big enough to stand it in to catch the drips) so putting one on the lid would be more convenient.

FYI I measured the temperature of the water vessels in three [cool] places around the house and the lowest yesterday (early evening) was 20.5. So I think I'll have to reduce the temperature by a couple of degrees when it's fermenting, just to offset the heat that's generated.

I also have one more question: once fermentation is finished what temperature will it be ok to leave the fermented beer to stand at? I expect I'll need to leave it a week or so to settle (and I might decant into another FV for an extra week to let further sediment fall to the bottom). Should it be OK at 20/21 degrees during this time?

Many thanks

[the_great_okapi]

Yes, it will be fine at 20 degrees. I would usually rack it off the yeast at two weeks (from pitching) to a secondary vessel if you are going to wait for it to settle a bit more. Colder than 20 degrees is preferable as it settles quicker.

If you are going to keg, you may as well put it straight in with some gelatin/isinglass or other finings and let it mature there.

[Toad]

Hi Mr J,

I brewed my first kit during a really warm spell a few weeks ago. Managed to get FV down to below 24 C (from 28 C) just by draping a wet towel over it, across the top and down the sides a bit. To cool another few degrees use a fan to increase evaporation. Need to keep the towel wet all the time.

I put this in the bath (undisturbed, we used the shower instead!), but could use a cheap tray, like cat litter ones if big enough.

Cheers, T.