Warning all fermenters
Here's a few things you need to know.
One thing that doesn't often get talked about is the temperature of fermentation for the home fermenter and while generally most things work out ok because the house temp stays within a nice range there are occasions when it gets to the extreme and well that is just not safe....
So if you have things bubbling away on your bench and the weather kicks it up a knotch, you'll need to know this.
We have been experiencing insane 37- 47 degree heat, that's 98-116 degree Fahrenheit for you North American folks, which is way above happy fermenting temps, which leads me to think...do you know what to do to help your ferments from overheating?
These include sauerkraut, kimchi, pickles, brines, and dry salted ferments.
These guys like a temp between 15-22 degree C (60-75 F)
In fact Sauerkraut really does not like it much past this temp range at all as the type of lacto baciilus bacteria that proliferates at these high temps is lesser in quantity and quality, Making your sauerkraut not as rich in beneficial bacteria as those produced in the ideal range and tends to be soft and can even go bad.
The same can be said for your kimchi's and pickles.
Brines and dry salted ferments are a little more sturdy but the bacterial activity will increase so you may have a few jars bubbling over and onto your bench so best to place a plate under each jar. Also watch the water/liquid levels once the temperature cools down again as the contents will shrink and may go moldy if there is no liquid left.
So how to cool down your ferments in these heat waves?
1) Water baths
Fill a bath, eskie, large tub up with water so your fermentation jars are 1/2-3/4 submerged in the water. You can place some ice cubes in the water also to keep its temp closer to the 22 degree mark.
This will help to prevent the wrong bacteria proliferating in such high heat. This is for any jarred vegetable ferment like sauerkraut, pickles, kimchi etc.
2) Fermentation Slowing Device AKA - a fridge
Place your jars in the fridge for the short term heat wave, this is not ideal for long storage as it halts bacterial growth, the fermentation process will kick back in once you take it out and in warms back up to that 15-22 degree C mark.
3) Wet towel
Any large ferments that can't be moved like crocks, large jars etc can be covered with a wet/damp towel to keep the temp down. Being a larger vessel it will take longer for the high outside temps to take hold anyway but they do need a little attention. Also keep a close eye on the water seal levels of any crocks.
4) Watch for leakages.
Even stable, well matured ferments are brimming with live bacteria that will go bonkers in such heat so watch that they don't overflow, crack or spill messing up your shelves and loosing all that great liquid.
5) Yeasts/moulds/slime yuck
High temperatures like this increases the likelihood of unfavourable outcomes in your ferments. Watch for yeast and mould growth. A white film of yeast is harmless, yeast cracks when touched and sits flat on the ferments unlike mould which is furry and tends to stay like a little island. Mould, any mould, is bad! Unfortunately that means throwing out your entire jar as mould has neurotoxins in it and you just don't want to be eating it. Lastly slime, yuck! Slimey textures in your ferments is not a good sign, the increased viscosity and thickening of your fermenting solution is a sign that the wrong bacteria or yeast has taken hold or the sugars were released too fast. Not only is it unfavourable in texture and taste it may also make you sick.
1) Bottled drinks
Any liquid that is up to second fermentation and is already bottled will need to go into your fridge. The heat speeds up the sugar eating bacteria and yeast and can easily cause and explosion. You can take the bottle out of the fridge once the heat wave is over to continue your secondary fermentation and increase carbonation.
2) Water Kefir
The best bet is to just put it in your fridge as the fermentation time increases rapidly and your brew can turn acidic, killing your grains. If you don't have fridge space then change the water and sugar frequently, may be as short as every 8 hours. Keep them as cool as possible and again watch for increased second fermentation time in bottles to avoid explosions.
Kombucha is a really robust ferment and will cope with the heat but the ferment may be different to normal as the type of yeast and bacteria that flourish will be those that prefer the higher heat rather than the usual 18-25 degree Kombucha. SO it may taste more yeasty and be higher in histamines. It will also be a much faster ferment, reducing the usual 14 day brew to 5-7 days. The mother culture (SCOBY) will also be likely to be thicker than usual. Again... any bottles of kombucha second fermenting in sealed bottles will need to be refrigerated to avoid explosions
4) Ginger Bug
Your Ginger Bug starter culture will be very active in the hot weather so if you store it in a sealed jar make sure you open it up, and cover with a cloth. Feed the Bug with sugar to make sure its not depleted of food after the heat wave. Any Ginger soda in sealed bottles...you guessed it....go into the fridge until after the heat wave. If they are not fizzy yet, you can always take them out again to reactivate the culture.
Ultimately remember these are living organisms and the heat affects them just like it does us and sometimes the results are not so desirable. #keepitcool Ferments happy place is between 15 and 22 degrees Celsius.
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Until next time
Keep cool my friends