Nottingham at high temps

[tubbsy]

I put down an Imperial Stout on Tuesday on the Nottingham yeast cake of a Golden Ale. The wort was aerated while filling the fermenter and it has been under 15psi from the start to keep the expected big krausen under control. What I didn't plan very well was the temperature. I was expecting to ferment at ~20C and given our current ambient temps of around that didn't expect any issues, but the yeast had a field day and the temperature got up to 32C. It's still under pressure today and has slowed down considerably and the temp is down to 25C, but will what can I expect from it getting to 32C?

 

[yankinoz]

You're in uncharted territory. Unpressurised, fermenting at even 25, Notty throws a lot of esters, . At 32, who knows, but I'd bet on heavy fusels. Would pressurising curb all that? Maybe someone here has had an experience like yours and can offer a forecast, but I doubt it.

So keep us informed and be glad you weren't doing a cream ale or faux lager that would highlight any offtastes.

 

[MHB]

Yank is right. Why anyone would want to pressure ferment an ale (or a lager for that matter) is beyond me. I know its trendy but it is a pretty silly idea.

Yeast makes heat when it ferments; working hotter tends to make more fusels (higher alcohols) during the ferment. With a lot of yeast it makes all the heat quickly. Esters are mainly made during the early stages of fermentation as the yeast is reproducing. With the amount of yeast you had at the start the reproductive phase was probably pretty short as a lot of yeast will consume all the available Oxygen very quickly then start the ferment, so esters are likely to be lower than you would get from underpitching.

There is a bunch of other stuff that will happen too, it gets a bit more complex, but the average age of the yeast cells goes up, so you get more dying cells and the heat accelerates their breakdown (Autolysis) and you get a bunch of other off flavours.
To reduce the harm get the beer off the old yeast ASAP, rack the beer to another fermenter, or even a keg. Let it finish fermenting (cooler) and taste it to see if it’s drinkable.
Next time it might be a good idea to work out how much yeast you need (there is a recommended pitch rate for a reason), invest in some temperature control, do a bit of planning so you get a good clean ferment and make nice beer.
Believe me, learning how to brew won’t shrink your ****, do the basics right and you will make better beer.
Mark

 

[tubbsy]

I don't normally bother with pressure fermenting right from the start of the ferment and only did this time as I expected it to take off like a rocket and make an unholy mess. I couldn't put it in my ferment fridge as it has a German Pils in it, but I did have temp control on it but as I didn't expect it to get so hot, all I had was a heat belt to keep the temp UP, not down.

I'll transfer it over this arvo and see how it tastes

 

[tubbsy]

Sitting at a more reasonable temperature of 22C this afternoon. Transferred over to another fermenter and took a sample. Tastes high in alcohol, but nothing "bitey" that I assume the fusels would be like. Tastes pretty decent to my untrained palette. Maybe I got lucky?!?

Anyway, the gravity is down to 1.013 from 1.092 in less than 48 hours which I calculate to 11.2%. I'll give it another week then cold crash before transferring again where I'll add some oak. I'm this far in now I may as well see it through...

 

[yankinoz]

Let us know when it's done. I'd be wary trying more than a short glass to start. At that abv and following that warm fermentation you may get a scheissenwagen (shitload) of hangover producers.

For future reference, cherry flavours go well in Imperial stouts, and I'm not a fan of most beers with added fruit.

 

[tubbsy]

Let us know when it's done. I'd be wary trying more than a short glass to start. At that abv and following that warm fermentation you may get a scheissenwagen (shitload) of hangover producers.

For future reference, cherry flavours go well in Imperial stouts, and I'm not a fan of most beers with added fruit.

Will do. I've got a party in April so I might keg half (it's a 40L batch) and there are a couple young lads that are self-proclaimed hardcore drinkers who will give it a nudge.

And it's funny you mentioned cherries - when I tasted it there as a big chocolate note and I don't know if it was my mind playing tricks, but I also detected a decent hint of coconut. Sabro was a big part of the hop bill. So I straight away thought of cherry ripe.

 

[beerbong]

I put down an Imperial Stout on Tuesday on the Nottingham yeast cake of a Golden Ale. The wort was aerated while filling the fermenter and it has been under 15psi from the start to keep the expected big krausen under control. What I didn't plan very well was the temperature. I was expecting to ferment at ~20C and given our current ambient temps of around that didn't expect any issues, but the yeast had a field day and the temperature got up to 32C. It's still under pressure today and has slowed down considerably and the temp is down to 25C, but will what can I expect from it getting to 32C?

I once did a Barley Wine with a double dose of Nottingham and it went completely mental. Massive blowoff straight out the air lock, mess everywhere, generated so much exothermic heat I thought I had a problem with my heating. Initial fermentation was so violent and fast but I still left for a long while in fermenter to be sure as I thought it was going to be total failure. That was over 2 years ago and I am still enjoying perfectly carbonated bottles of lovely BW now. Nottingham yeast is volatile stuff if you mess with it

 

[tubbsy]

I once did a Barley Wine with a double dose of Nottingham and it went completely mental. Massive blowoff straight out the air lock, mess everywhere, generated so much exothermic heat I thought I had a problem with my heating. Initial fermentation was so violent and fast but I still left for a long while in fermenter to be sure as I thought it was going to be total failure. That was over 2 years ago and I am still enjoying perfectly carbonated bottles of lovely BW now. Nottingham yeast is volatile stuff if you mess with it

Yeah, I've had some craziness with Nottingham before, but this was next level. I'm not even sure my fridge would have kept up with it! I'm very glad it was under pressure because crap would have gone everywhere. Even as it was some of still made it's way out of the spunding valve.

 

[user 37368]

Yank is right. Why anyone would want to pressure ferment an ale (or a lager for that matter) is beyond me. I know its trendy but it is a pretty silly idea.

That statement is pretty silly given the amount of large scale professional breweries and science available on the effects of pressure & fv types.

 

[MHB]

That statement is pretty silly given the amount of large scale professional breweries and science available on the effects of pressure & fv types.

Point me at any from professional breweries, other than a couple of low cost mass market lagers, as I can’t find any.

The two world respected brewers in the YouTube you linked are saying exactly the same thing. Pressure early is bad! It’s fine to Spund or Bung the fermenter when there is a couple of percent left to form condition (fizz).
Mark

 

[user 37368]

Sure they say don't spund early, but that's a lot different from your statement.

If you want to watch it again they point out there is a lot of pressure using large conical FV's already.

Also did you jsut call wienstephaner a low cost mass market lager? hahah.

 

[MHB]

Anyone else, probably everyone else, understands that pressure fermentation refers to applying pressure early in the ferment as opposed to late for conditioning. I'm sorry if I didn’t make that abundantly clear for those with really limited understanding.

Note that there is a lot of difference between hydrostatic pressure in a tall lager fermenter and that in the only ale Weihenstephaner make, they brew in shallow open fermenters, to reduce pressure (both sorts); might help if you thought about that.

If you do have any of the information from "large scale professional breweries and science available on the effects of pressure & fv types" that points to benefits of pressure fermenting, especially in ales, then I would really like to see some. Happy to be proved wrong, but lacking anything other than an opinion, I will stand by what I said.
Mark

 

[tubbsy]

So it's been sitting in 2 kegs for 2 months now - one as is and another with some oak sticks. I put the non-oaked keg on gas last week and trying my first glass tonight.

And it's turned out well! Doesn't taste boozy, nice and thick and a nice balance between hop bitterness and roast astringency.

I had half a pack of carb drops left over and I've put them in the oaken keg. I'm going to leave it for another 6 months or more and see how that goes.

 

[yankinoz]

All's well that ends well, and thanks for updating.