Fermenting temperature

[MarkF_2703]

Thanks Kev, its sat at 18 deg ATM, the bubble wrap approach, but no rise yet, suck it and see, the fridge has to be 30 years old now, served in the garage as bait and beer storage fridge for nearly twenty, has no issues getting the ambient down to 1 degree for crashing, its all a new adventure, but like gardening it takes time to see the results and work out the best methodology, that's why I don't garden

My query was that the instructions say room temp not wort temp, did Muntons take the differential into consideration? The yeast has nothing on the packet to give a temp range as you get with none kit yeast packets. Hence the narrow temp range for room temp of 18-20 degrees?

[Kev888]

Instructions on kits generally assume a simplistic stance; I guess they don't want to put beginners off. Muntons would have specified 18-20c room temp for simplicity. It is a fair compromise; the wort temperature wouldn't drop too low for the yeast to work well, and the period during vigorous fermentation wouldn't rise too high in a batch of homebrew proportions - but rise it would whether desired or not.

But with temperature control you can go beyond that to be a bit more discriminating, and so keep the wort itself at your desired temperature even during its vigorous, self-heating stage. Some people may even choose to vary the desired temperature, for instance increasing it by a few degrees toward the end of fermentation, to help the yeast finish.

What said wort temperature actually should be depends on the yeast characteristics and what you are trying to achieve. In general, warmer temperatures result in more character from the yeast, which may be desirable in some beers/yeast-strains and less so in others. Taking things further, go too low and the yeast may struggle, stall or not get going to begin with, too high and there will likely be excessive/unpleasant flavours - much too high and the yeast may not survive.

Unfortunately kit yeast don't often have a lot of info on them, but they are usually fairly tolerant. Other specific strains will describe their own preferred ranges of actual fermentation/wort temperature. With experience of the yeast, you can choose how closely to abide by these guides to achieve your own ends. But if in doubt then for ale yeast something around 19c to 21c is generally a safe/neutral starting point (i.e. the wort temperature). Lager yeast are lower, but not all lager kits actually use lager yeast so be guided by the instructions.

[MTW]

NB: I must have been typing this at the same time as Kev above, but I will continue to post it here unedited, if only to show unity of good advice! (though I'd go slightly cooler, as per below)...

Ignore the instructions; you've got much better advice on here, honestly. And I can say that having done maybe 40-odd kits before brewing from grain in the last few years. They're written to make the process sound as simple as possible, which is fine, until you realise that there are a lot of ways of producing bad beer. You just need one good one. I'm pretty sure Muntons haven't compensated for anything there.

Without knowing the strain of the kit yeast, I would certainly go on the low side. [I once heard Nottingham strain is quite common in kits and can be nice and clean, but gets estery on the top end of 'room temperature'.] How big was the sachet by the way? I've seen some as little as 6g for a 23L kit. If it was 11g+ then you probably pitched as much as much as most people would if they'd bought a separate sachet, for a typical 1.040-50, if not higher. Hopefully, you rehydrated it. Pitch rate is a big player in the level of esters you will end up with, along with temperature and the level of essential nutrients for the yeast in the wort. I know you asked about temperature and I may be going off topic, but if you end up with a very estery beer despite following the good advice on temperature here, it may well be down to something else. Keep it on the low end of that range, and you've hopefully ruled it out, and when you have a named yeast in your hand, and plenty of it, which you know to be suitable at a given temperature for what you want, then you can adjust accordingly.

[Fil]

My query was that the instructions say room temp not wort temp, did Muntons take the differential into consideration?

Its Highly probable they didnt.. And have probably allowed a grammar/syntax checker or even worse a marketing bod loose on the final draft

The yeast has nothing on the packet to give a temp range as you get with none kit yeast packets. Hence the narrow temp range for room temp of 18-20 degrees?

while the yeast will no doubt perform outside this narrow range, its probably the range that will promote the most desirable flavour impact from the fermentation. for the specific beer kit its sold with, they may also sell a belgian tripple kit with the same yeast but suggest a warmer fermentation temp.

generally speaking he yeast will perform slower and 'cleaner' at lower temps, while when warmer will become more active and produce more 'by products' or more complex flavours, some of which may not be in keeping with the beer or even nice
and Im using 'words' cos i am not a microbiologist, and dont really know wtf im talking about..

If interested in the subject of yeast and their impact on the brewing process, the excellant book by C White and Jamil Zainasheff Yeast, is an extreamely accessable read even if your not a lab rat https://www.amazon.co.uk/Yeast-Practica ... 0937381969

[WalesAles]

and Im using 'words' cos i am not a microbiologist, and dont really know wtf im talking about..

HaHa! Fil, You been on the HomeBrew again?

WA

Sent from my car

[Fil]

HaHa! Fil, You been on the HomeBrew again?

WA

Sent from my car

Fair assumption, but like many when sampling i become expert in every subject

[MarkF_2703]

All taken on board thank you, sat nicely at 18 degrees ATM, no krausen (sp) rise yet, but I do have positive pressure in the fermenter, so something is happening, having been doing kits for over 2 years now, I am looking forward to upping the game, just want to get the fermenting bit under my belt, after all whats the point investing time and money producing a wort and failing to give it my best fermentation.

[McMullan]

...after all what's the point investing time and money producing a wort and failing to give it my best fermentation.

Hear, hear!

[MarkF_2703]

So far looking good, every time I have looked the temp is less than half a degree from 18, most of the time it is 18 or 18.1, just dropped a sample as there hasn't been a very active bubbler, but I think this yeast is a slow plodder, the sample after 6 days is full of CO2 nice head, left to stand and lots of yeast dropped out, so very pleased it is heading in the right direction. Quick taste and still very malty.

[TheSumOfAllBeers]

Mark: the transformation of my beer since I got temp control together has been massive. Precise. Clean. Grain to glass in a couple of weeks (14 days w/ bottle conditioning is my record).

When you start to ferment cool and clean your fermentation will be slower - the yeast can't supercharge its metabolism with its own exothermic heat.

If you are used to a free rising fermentation of 45 gravity wort being finished in 2-3 days, add another day or two if you are fermenting lower.

[MarkF_2703]

Probably the wrong place, but its been at 1.015 for 3 days now, 3.8%, instruction say below 1.014, but I guess that depends how you read/calculate, upping the temperature 2 degrees until Friday which is 14 days since activity of yeast, hoping that will confirm fermentation has completed plus give it the Diactyl rest everyone talks about, I have fallen foul of that in a few beers so far, butterscotch taste.

The aim was 4.0 ABV so I am close. Plan is then to rack it off to another bucket then cool it with finings for 3 or 4 days before kegging and force carbing.

Any glaring flaws in this thinking, other than the racking off introducing risks to bacteria, so far it never has for me.

[rootsbrew]

One option would be to taste a small sample before fining and racking. If you detect more RS than you like or expect, scan through the forum for addressing a stuck ferment. If there's material for yeast to metabolise, it'll do so.

Not the most direct answer but hope it helps a bit.

[Kev888]

One gravity point above the instructions is very minimal; it is only a guide to begin with, and readings have cumulative inaccuracy, based on accuracy of your hydrometer plus the reading method, as well as temperature of the wort (hydrometers are designed for one specific temperature and need compensation if used at others).

So it is essentially within reasonable accuracy of expectations, and so very likely finished, or thereabouts. But yes, it is a fairly high Final Gravity and whilst that is appropriate for the style it could perhaps have gone a point or two lower, so I agree theres justification for being at least a little cautious of it potentially dropping a tad more, especially if you intend to bottle.

[MarkF_2703]

Thank you, I have had a taste already, as you do, taste is clear of any off flavours, I think it is close enough to not worry about being stuck, will check again Friday, tap on the fermenter is the best thing I ever did.

What is RS?

[rootsbrew]

Sorry, short-hand for Residual Sugar. Supposedly, humans can notice anything from about 5g glucose/litre plain water, which is upto about 0.3% - i.e. enough to consider doing something, which includes waiting (waitjng takes a lot of effort I find!).

Thinking aloud here - if you intend to fine your beer, re-measure the specific gravity once it's cleared. It might well drop a point or two, plus while the yeast is bunching up, it's still working towards dry. Once clear, mix in a tiny wort of malt extract and fresh yeast (e.g. a bottling strain) about 6-8hrs before bottling - the new activity might nudge the beer a bit more. Worst case scenario is it becomes a smidge over-primed, which'll settle on pouring.