Small batch AG Brews - Fermentation

[Neil Whittaker]

Hello all,

So my first AG brew was a small batch DIPA.
See: https://www.thehomebrewforum.co.uk/threads/neil-brewday.85379/

My issue is, with my vast experience (2 kits) doing 23l batches, the fermentation takes over a week and the airlock activity slowly reduces as the days go by.

My 12l batch went like a rocket for 2-3 days then nothing much is happening for a couple of days.
Do you think it is early to take a gravity reading?
There is still a good foam on the top, but just wondered if you experience a different fermentation timing on small batches.

I think i just talked my self into taking a gravity reading. :-p

 

[Neil Whittaker]

Extra info,

It was at 19c in my Fermzilla @ 10psi.
after 3 days, It then dropped to 5 psi, so i suspect an air leak. so maybe it is still going but escaping from the seal and not the spunding valve.

 

[Cheshire Cat]

I would leave it until at least day 5 preferably day 7. With small batches the yeast to volume ratio will be higher so the wort might ferment quicker.

 

[terrym]

If the fermentation is obviously still underway why do you need to take an SG reading?
Some brews take longer/shorter than others, and there are many factors that come into play including yeast used, temperature, OG etc.
Leave it. Its done when its done.

 

[Cowman]

Are you using the same fv for the 12l brew as you are for the 23l ? If so it can be because there's a lot more headspace so it takes a lot longer to build up pressure to bubble the airlock. Don't rely on the airlock too much as a measure of fermentation. I'd leave it to the 14 day mark in any case

 

[Neil Whittaker]

The good thing about the Fermzilla is you can see the fermentation in action. The krausen looks to still be bubbling.
There might be an easy explanation. The 4 year old might have turned the spunding valve down, which would explain the pressure drop.
I'll check when I get back in tonight and see if we have more pressure.

I've also raised it from 19c to 19.5c and will increase again by 0.5 tomorrow.

If the fermentation is obviously still underway why do you need to take an SG reading?

Because I'm daft and want to know whats going on. Also, would I not want know for dry hopping purposes?

Are you using the same fv for the 12l brew as you are for the 23l ?

Yes, but it was upto 10psi and kicking out loads of C02, so the head space was already pressurised.

I'll take a chill pill til 7 days like at least. :-)

 

[terrym]

Because I'm daft and want to know whats going on. Also, would I not want know for dry hopping purposes?

You are blessed with a fermenter that has a clear wall so can see what's going on. You will know when things are coming to an end because the beer will look less active and will start to clear. Others like me just leave it for several days possibly relying on an airlock to tell us if the fermentation has stopped or nearly stopped, at which point the hops can go in. Brewing beer is something that takes patience and a day or two longer at the front end is nothing really especially if you have a beer that needs conditioning for weeks.
And in my view taking SG readings every two days doesn't make any difference to how the beer will turn out, and arguably the only SG reading that is truly important is the FG because knowing that will ensure you are satisfied you can safely package your beer without risking bottle bombs.

 

[Neil Whittaker]

Cheers Terrym,

I will put it out of my mind a while and enjoy tonight home brew meetup.
Fermzilla is both a blessing and a curse Lots of advantages, but loads of seals and parts.
I hope to use the collection jar to harvest some yeast during this fermentation, see how that goes.

Here is a picture as of this morning:

 

[terrym]

@Neil Whittaker
Looking at that healthy fermentation I think you will able to safely leave it alone for several days before your hops can go in.

 

[Neil Whittaker]

Oh nice one. I lack some experience so I really appreciate the advice.

I'll make sure I give an update.