Newbies first brew: when to stop fermentation

[awkwardbob]

Hi there,

I’m in the process of my first ‘run’ and I have a question about when to stop fermentation...

I’m doing an all-grain brew and the recipe had a target OG of 1.059 with 21 L and a final gravity of 1.015.

I fell short of the target OG with 1.044 and 19 L and the wort is currently fermenting at breakneck speed at 20 C.

After a slow initial start, the yeast has gone a bit mad and is hurtling towards that target gravity of 1.015, currently sitting at 1.019.

My question was: Do I just let everything continue until the FG levels off ? -will it naturally stop when it reaches somewhere around the 1.015 mark ? Or should I step in and move to bottle the batch when it gets to 1.015 ?

Thanks for your help, it’s much appreciated !

Bob

 

[user 18729]

Leave it alone until it’s completely finished before bottling regardless of your intended FG

 

[awkwardbob]

Thanks for that,

Just wonder though, if the final gravity winds up very different from 1.015, will it have a big effect on the flavour ?

Also, while it may level off and I could be worrying unnecessarily, the recipe suggested a 10-day fermentation At 20-22C, my batch seems to be progressing more rapidly. Is this ‘normal’ or does it depend on a whole load of factors ?

Thanks again !

Bob

 

[Horners]

Bob

I am no expert but a couple of things I have picked up:

1. The higher the finishing gravity the sweeter the beer. Gravity effectively being a measure of sugars in solution. If FG is high it means less sugars consumed by yeast and therefore less alcohol.

2. Unless you have non fermentables in there (eg lactose) 1019 looks high given starting gravity. Search stuck fermentation on here.

3. Looks like you are using a tilt, whilst Understand these are useful for tracking progress, I would corroborate with a hydrometer reading.

 

[awkwardbob]

Thanks Horners,

The fermentation isn’t stuck, it’s hammering along at breakneck speed, it’s reading 1.019 this morning after 2 1/2 days.

I suppose I’ll leave it running and see where it goes. -and will double check with a traditional hydrometer.

Thanks again

Bob

 

[Cheshire Cat]

If you're using an airlock on your FV then wait until the bubbles stop or there's more than a minute between them. Then take the SG.

 

[kelper]

The SG drops rapidly in the first few days and tapers off such that it may drop only one or two points per day. It's best to leave it in the FV for two weeks minimum.

 

[Horners]

Thanks Horners,

The fermentation isn’t stuck, it’s hammering along at breakneck speed, it’s reading 1.019 this morning after 2 1/2 days.

I suppose I’ll leave it running and see where it goes. -and will double check with a traditional hydrometer.

Thanks again

Bob

Oh right in that case just leave it alone till 14 days in and then measure with Hydrometer 3 days running same reading and you are good to go.

Main problem which I am guilty / was guilty of too is impatience. As soon as this one is done, get the next one on.

 

[kelper]

With two FVs and three PBs you can start a brew every two weeks and always have beer available!

 

[terrym]

@awkwardbob
Whats the rush?
The primary fermentation normally finishes when the yeast has consumed all the fermentable sugars or thereabouts, and what is left is alcohol and the sugars it can't ferment. And the time it takes to do that is dependant upon a number of factors including the yeast used, temperature and the wort mix. You don't stop it, you leave it alone to do its thing until its finished whenever that is (provided its not 'stuck' at a higher OG than expected, which yours isnt). Some beers/yeasts are finished in 3/4 days, others can almost reach the FG then take days for the final 2 or 3 points, and others just chug away after the initial aggresive ferment for weeks although latter is not usually the case. And even when the primary has finished its good practice to rest the beer for a few days longer to allow the yeast to clean up its own impurities created during the fermentation and also to allow the beer to substantially clear ready for packaging. And a rule of thumb for the new brewer before he/she gets more experience is to leave it in the FV for 2 weeks which normally covers all the time needed, although sometimes this is not long enough. And if you have an airlock don't rely on it, your lid may be leaking although it appears OK, use your hydrometer to tell you the state of play
Finally I suggest you leave it alone for the full two weeks and overcome your desire to peek inside. Every time you open up the FV there is a very small risk of infecting your beer. Then take an SG reading then another the following day and if they are the same you can package.
And above all remember 'Patience is the friend of the homebrewer' which will stand you in good stead as you develop your brewing technique.

 

[Rodcx500z]

I am learning patience I should have loads having made bread at work for 30 years but this is beer Leave it for 2 weeks

 

[kelper]

Bread and beer are completely different. You never hear people saying, ' man cannot live by beer alone'. Bread is ready in one day. Beer takes weeks.

 

[awkwardbob]

Hi Folks,

Thanks for all the replies, I’m more than happy to let it do its thing, I was just worried that, if it’s current rate of attack is to be believed, it might horribly overshoot it’s target FG.

I like that the tilt lets you track without having to open up the fv but will check the readings once they stabilise -although I suspect it’ll be more accurate than I’ll be !

One more quick query, if I may, but the received wisdom seems to be to dump the dead yeast every 2-3 days as it settles (it’s a conical fermenter) does that sound about right ?

Thanks again

Bob

 

[terrym]

Thanks for all the replies, I’m more than happy to let it do its thing, I was just worried that, if it’s current rate of attack is to be believed, it might horribly overshoot it’s target FG.
One more quick query, if I may, but the received wisdom seems to be to dump the dead yeast every 2-3 days as it settles (it’s a conical fermenter) does that sound about right ?

If it overshoots by a bit, it overshoots. So what? You can't stop it. FG figures supplied with recipes are usually only estimates, although actual FGs won't be too far out under normal circumstances. Just relax and let it do its thing.
Cant help on dumping the yeast. I'm sure others who have conical fermenters will be able to advise,

 

[Rodcx500z]

All my AG brews have over shot fg some by a considerable margin but that was down to the yeast I was using, my last one I used mj-m21 and it was more or less bang on, if it goes over just enjoy a stronger dryer beer

 

[Pete Mc]

When brewing all grain the mash temperature has an impact on the amount of fermentable sugars, which will raise or lower the fg. Just another variable to be aware of, all the advice above looks great.

 

[awkwardbob]

Thanks for all the advice,

My mash was 60 mins at 65C with a 10 minute spell at 75 C to finish off. -I probably didn’t agitate enough or sparged too quickly.

Yeast is a WLP4040 Midwestern ale yeast...

Quite glad of the extra time to get my bottles ready !