How important is temperature in fermentation?

[Snrub]

Hi everyone

I'm relatively new to brewing, started in January and all extract brews so far. 7 brew days done so far with 2 x 5 gallon brews each time. Learned an awful lot as you do, but only one batch totally ruined so far!

My question is about temperature - I put my FV's in a spare room. In Jan/Feb/March I was kind of in control of the temp, as I heat the house to 18-20 degrees and used one of those magnetic strip thermometers in the FV to measure my brews, they were consistently at 22-26 degrees.

As it's got warmer, I'm not heating the house but have left the brews in the same place. So a) the ambient temperature will have been fluctuating while fermenting and b) my last brew day (3 batches) was in the week before the recent heatwave, so may have hit temperatures approaching 30 degrees.

I bottled those batches last week, and all looked good with the process - vigourous fermentation in all 3 batches within 12-16 hours and all 3 reached FG of 1.010-1.014 after 2 weeks.

When I taste them I'll surely learn, but I wondered what people's thoughts were about the influence of fermenting temperature on a batch of beer? Should I be paying more attention than I am? I know people use modified fridges and so on to maintain temperatures, so I'm guessing they'll tell me it's hugely important, right?

Cheers,
Mr Snrub

 

[Clint]

Mine definitely improved with temp control. I think it's more important at the start of fermentation. A brew fridge is easy to set up but some people use a brew bag over their fv filled with frozen bottles of water or ice packs.

 

[Snrub]

When you say "easy to set up" - do you have any guides? I've read a lot online, and to be honest I glaze over reading what look like complicated electronics! (I actually read more about this for drying meat than for brewing, but the principle's the same).

Do I just need to crack on and try something? I do have a massive american fridge-freezer in my garage which I've saved for just this purpose.

Any help much appreciated!

 

[Thumper]

It's not very complicated, you just need to nail a greenhouse heater to the inside and buy an inkbird. Hell, I'd do it if I had a spare fridge and some spare space, and I can barely wire a plug!

 

[tobyjrn6]

My first 5 or so batches were all ruined by high (ambient) temp vs nottingham yeast - tasted like hoppy paint thinner. That said provided youre sitting in your yeast's ideal range youll be pretty safe even if it fluctuates and like clint said particularly the first day or two when the yeast can go overboard with all the sugar and produce fusel alcohols (havent noticed the same problem with bottle conditioning because so little fermentation is occurring.)

I'd definitely recommend getting a ferm fridge set up, all you need to do is buy an inkbird and maybe bypass the thermostat on your fridge/freezer but its a 5-10 minute job

 

[BarnBrian]

My first 5 or so batches were all ruined by high (ambient) temp vs nottingham yeast - tasted like hoppy paint thinner. That said provided youre sitting in your yeast's ideal range youll be pretty safe even if it fluctuates and like clint said particularly the first day or two when the yeast can go overboard with all the sugar and produce fusel alcohols (havent noticed the same problem with bottle conditioning because so little fermentation is occurring.)

I'd definitely recommend getting a ferm fridge set up, all you need to do is buy an inkbird and maybe bypass the thermostat on your fridge/freezer but its a 5-10 minute job

Fridge will make a world of difference to your brewing process, do it.
No need to by pass the thermostat, just leave it on maximum cooling.
Don't "nail" the heater, use silicone.
ITC 1000 is pretty straightforward, but if this scares you just get an Inkbird 308 , it's dearer but you don't need to do any wiring.
Heater and sensor wires should feed through the drain at the back of the fridge, this may need to be enlarged slightly with a drill.

Brian

 

[Sandimas]

When I taste them I'll surely learn, but I wondered what people's thoughts were about the influence of fermenting temperature on a batch of beer? Should I be paying more attention than I am? I know people use modified fridges and so on to maintain temperatures, so I'm guessing they'll tell me it's hugely important, right?

Yes, too high or too low can result in a ruined beer. Too high (above 25C) you'll end up with off flavours which can make it undrinkable, too low (below 18C) and you risk a stuck brew. Most people try to stick to 18-22C.

It can get a bit tricky to keep the temp low this time of year, but the rest of the year when it's cooler a simple solution to temp control is to put the FV into a large garden trug filled with water and use a 50W fish-tank heater in the water to maintain temp.

 

[Manxnorton]

I speak for lot of brewers on this forum that experiences fermenting your brews in an un temp controlled house...end of the day for me i might of done it with ‘fingers crossed’ and hope for the best!
For me I found after a lot of fanny in on with ferm chambers it was time to save the heartache and buy a fridge, greenhouse heater n an inkbird..
You can get good deals in the net greentree etc.
For me a tall fridge is my Best Buy, large enough for my SS Brewbucket and a white placca FV.
You’ll never look back..
Bri

 

[chthon]

Temperature is important, but on the other hand I would like to convince people that finding space for putting a brewing fridge is not always possible! So, would you then say, if you cannot install a brewing fridge (due to lack of space), that you might as well not start homebrewing?

I try to be creative about it. I do have a spare room, but that is more like an office and a library. Not suited for putting a brewing fridge. I have also a part of the house that is situated at the north side, and is always relatively stable in temperature. In the winter I use this to brew lager (bock), and the spare room when not heated also has a relatively stable temperature.

 

[AdeDunn]

Temperature is important, but on the other hand I would like to convince people that finding space for putting a brewing fridge is not always possible! So, would you then say, if you cannot install a brewing fridge (due to lack of space), that you might as well not start homebrewing?

I try to be creative about it. I do have a spare room, but that is more like an office and a library. Not suited for putting a brewing fridge. I have also a part of the house that is situated at the north side, and is always relatively stable in temperature. In the winter I use this to brew lager (bock), and the spare room when not heated also has a relatively stable temperature.

No, I'd say to just change the yeast you use when it gets warmer. Amongst the dry yeasts, Saison yeasts, wheat beer yeasts and Belgian yeasts all produce more flavour when fermented warmer, producing better beer because of it. During cooler weather, there are still yeasts that are more tolerant of warmer fermentation. Mangrove Jacks M44 West Coast for example has a range up to 23 degrees C, and my experience so far of using it (I pitched 2 packets in an AIPA on the 12th, and a taste of the sample jar yesterday was delicious!) is that it stays neutral within this range too. M36 Liberty Bell has always seemed quite happy a bit warmer too.

On the warmer side, I've obtained excellent results using both Belle Saison and Mangrove Jack's M29 French Saison warmer, pitching at 18 degrees C, letting it free rise to 24 degrees C, then ramping it up to 26 degrees C. A few people have said "but I don't like Saison!", I don't make traditional Belgian Saison though, I make hoppy Saisons that are more of a Saison/AIPA hybrid, they just finish dryer, with lots of yummy, fruity, hops.

 

[Sandimas]

So, would you then say, if you cannot install a brewing fridge (due to lack of space), that you might as well not start homebrewing?

No, I've done 136 brews without a brew fridge - you just need to be aware of temperatures and take action accordingly. I usually stop brewing June-Sept (apart from Belgian beers) because the house is too hot. I brew lagers mid-winter when my north-facing downstairs loo gets down to 12C.

I'm brewing today and worried the house will be a little too warm with this weather, so I'm taking the thermometer into each room to work out which is the best. I've had a few beers ruined by fermenting too hot.

 

[Thumper]

Don't "nail" the heater, use silicone.

What Brian said. I was being flippant, they weren't actual instructions. Don't use nails!

 

[Snrub]

Thanks everyone, some helpful tips there. Be interesting to taste my most recent batches then!

I have 2 main take-aways from this, I'll test the ambient temp in all the rooms in the house and see which is most appropriate for a british summer, and i'll look at the fridge mod idea properly. Up to now I've been planning to make a curing chamber, but if it's a choice between meat and beer, we're going with beer!

 

[Gunge]

I'll be brewing on Sunday, and with the current warm spell set to ratchet up a notch by then, I'm thankful to have the means to hold the fermentation at a rock-solid 19C come what may.

 

[BarnBrian]

Thanks everyone, some helpful tips there. Be interesting to taste my most recent batches then!

I have 2 main take-aways from this, I'll test the ambient temp in all the rooms in the house and see which is most appropriate for a british summer, and i'll look at the fridge mod idea properly. Up to now I've been planning to make a curing chamber, but if it's a choice between meat and beer, we're going with beer!

As you've already got the fridge it's a no brainer, set it up with inkbird and heater. You won't regret it.

 

[Zephyr259]

I had the opposite problem and my house was too cold for ale yeasts except the Scottish strains. Inkbird is great, just plug it in and away you go. I use a 14W reptile heat mat as my heat source inside the fridge and it works great. All of a sudden my beers finish primary fermentation in 3 - 5 days and the ability to crash cool has greatly reduced the sediment I get in the bottles.

 

[BeerisGOD]

No, I'd say to just change the yeast you use when it gets warmer. Amongst the dry yeasts, Saison yeasts, wheat beer yeasts and Belgian yeasts all produce more flavour when fermented warmer, producing better beer because of it. During cooler weather, there are still yeasts that are more tolerant of warmer fermentation. Mangrove Jacks M44 West Coast for example has a range up to 23 degrees C, and my experience so far of using it (I pitched 2 packets in an AIPA on the 12th, and a taste of the sample jar yesterday was delicious!) is that it stays neutral within this range too. M36 Liberty Bell has always seemed quite happy a bit warmer too.

On the warmer side, I've obtained excellent results using both Belle Saison and Mangrove Jack's M29 French Saison warmer, pitching at 18 degrees C, letting it free rise to 24 degrees C, then ramping it up to 26 degrees C. A few people have said "but I don't like Saison!", I don't make traditional Belgian Saison though, I make hoppy Saisons that are more of a Saison/AIPA hybrid, they just finish dryer, with lots of yummy, fruity, hops.

Is the workhorse (mangrove) yeast available anywhere? Cant see it for poo on eBay or a few online brew shops
This one can tolerate 30c if I remember correctly

 

[AdeDunn]

Is the workhorse (mangrove) yeast available anywhere? Cant see it for poo on eBay or a few online brew shops
This one can tolerate 30c if I remember correctly

They discontinued it sadly.

 

[BeerisGOD]

That's pants
Mauribrew 514 it is then

Edit
Can't see this one either and tbh ive just noticed it always finishes around 1.020

Ive got a pack of Nottingham and I think some one on here had it at over 25c with no detrimental effects to the finished beer

 

[treebeard]

I usually stop brewing June-Sept

I'm in a similar situation, we live in a very small bungalow with no space either inside or out for a fridge and the coolest room is still too warm in the summer, my FV is a SS Chronical and it stands on legs. It's real bugger, my keg is almost empty and I need to get a brew on. :angry: