The temperature across the UK is set to plummet over the next week.
Nice if you like long fresh walks, not so nice if you’re yeast. Most strains of brewer’s yeast are reasonably robust and will perform adequately across a fairly wide temperature range. However, unless it’s a lager yeast, if it’s really cold then even the toughest of ale yeast may go dormant and simply refuse to finish the job of making your beer!
If you’ve just brewed or are planning to do so in the next week, how can you keep your fermenting beer at the right temperature through your brew?
Well, you could go out and invest in some more equipment and accessories to help keep your temperature consistent – but that’s just more expense and more stuff to store – and at HomeBrewtique we don’t like that!
Here are some quick and simple tips to help you ensure you don’t suffer from the dreaded “stuck fermentation” on these colder winter days.
1) Move your fermenter up higher… definitely get it off the floor or any cold surface. Place the fermenter on cardboard or a towel to help
insulate it from a cold surface.
2) Wrap some insulation around the fermenter itself – a towel or blanket will
3) Move your fermenter to a warmer part of your house – ideally you’re looking for a room where the temperature remains pretty constant. If at all possible you want to avoid huge swings in temperature. Your beer will be better if you ferment slightly colder but at a consistent temperature than if you subject it to a wide temperature range.
A good method to check if the average temp of a room is actually warmer then another is to put a jug of water in the room with a thermometer sitting in the water. Ideally leave it for 24 hours, or as long as feasible, checking at several points to gain an understanding of the
true temperature fluctuations, if any. Note that the liquid will be lower than the room temperature and will take a while to acclimate to the new room.
4)You can increase the thermal mass of your beer by placing it in a tub of water. A larger body of water will take longer to be affected by a change in ambient temperature… careful that you don’t make the water bath too warm but you could certainly put it the upper threshold of your desired fermentation temperature which will help raise the temperature of any cold beer. (sort of reversing the Big CHILL from your brew day!). Simply by sitting in a larger volume of water you are protecting your fermentation from a certain degree of temperature fluctuations.
5) If your beer has gotten too cold for too long then you may indeed have suffered from a “stuck fermentation”. The best cure for this (if none of the above works) is to re-pitch with fresh yeast. Make sure that you get your beer up to the appropriate temperature and then add a fresh batch of yeast.
If you think your yeast has been too cold for a while, it might be safest to extend the fermentation time for a few days before bottling, or check your gravity to be sure your fermentation has completely finished.
Remember to be sure you make note of anything that you do in your Brewer’s Notes so that you can refer back to it in future.