restarted fermentation due to hot weather

[mancdaz]

Hi All,

Only a few brews into my brewing career so still very much a noob.

My current brew had settled about 10 days ago, with SG readings 3 days apart not changing. I left it until this past weekend to bottle, and to give it a bit extra time for cleanup.

On about Friday, bubbling activity started again in the airlock. I thought maybe just due to heat expansion with the weather getting warmer, but it was regular and steady. By Saturday, I was back to a bubble about every 10 seconds. Took another SG reading yesterday, and it's dropped another 2 points. It's still bubbling away today, but slowing slightly. On Saturday, the temp on the FV was reading around 26.

Just wondering if this is 'normal', in a relative sense? I'm obviously going to leave it settle again until the SG readings are not changing, before I bottle. I'm guessing this is going to be quite a dry beer when it's finished.

 

[Dutto]

Very "normal".

A slightly increased temperature will very often re-start fermentation; and it's regularly used to kick-off a "stuck" brew.

If it still smells okay there's very little chance that anything has gone wrong.

 

[terrym]

It would be helpful if you told us what you are brewing (AG , kit etc etc) and what your OG was and what the current SG is, and what yeast you are using.
Otherwise wot @Dutto said.

 

[mancdaz]

It would be helpful if you told us what you are brewing (AG , kit etc etc) and what your OG was and what the current SG is, and what yeast you are using.
Otherwise wot @Dutto said.

It's a 'brew your own beer' IPA kit from The Range. OG was 1.044, it had stopped at around 1.008. It's now at 1.006, possibly closer to 1.005 (which would give 88% apparent attenuation), and doesn't appear to be finished yet. I'm not sure what the yeast was as it just said 'top fermenting ale yeast' on the packet.

 

[peebee]

I've just been explaining this in a different thread (different subject, but the same physics is at work):

https://www.thehomebrewforum.co.uk/threads/carbonated-during-fermentation.82524/

 

[mancdaz]

Thanks @peebee. Given that this has been going on for about 5 days now, and that I've dropped a couple of gravity points, I'm inclined to think it's more than just dissolved co2 from the initial fermentation making it's way out. Maybe it's a combination though.

 

[mancdaz]

Update: SG is now down to 1.002 (!) meaning an apparent 95% attenuation. Is this likely, or is something else odd going on here?

Bubbling has definitely slowed, but I don't want to bottle until it's definitely finished dropping. Can't go much more though surely?

 

[terrym]

My understanding is that ale yeasts rarely go below about 1.005, and my experience bears this out, plus most kit yeasts are done after about 10 days, so something is not right. So first have you checked your hydrometer by dunking it in clean tap water at the calibration temperature usually 20*C, when it should read 1.000. But if the reading is accurate and your SG is 1.002 and still falling you may have got a wild yeast infection which could take the SG down as low as 1.000 from what I understand. I have not had the misfortune to get one of those but others may have some experience of that and can advise on what to do, if anything.

 

[Drunkula]

What did you add to the kit? If it's a kilo of dextrose then beersmith says it'll finish at 1.001. I bottled this kit recently and it's the longest ferment I've had in ages - over 2 weeks it got down to 1.007 and stopped so I bottled it - yesterday I had my first bottle bomb ever. It happened right in front of me.

 

[Dutto]

......... I had my first bottle bomb ever. It happened right in front of me.

Hard to put a "Like" up! (Still think we need an "Oh crap!" or something similar.)

I hope you are okay, because Bottle Bombs are truly scary.

Apart from listening to my Mum's Ginger Beer bottles exploding in the pantry, my only other encounter with a bottle bomb was when I turned over an old beer bottle on Skegness beach. I don't know why (maybe it had been in a brush fire or had been sat out in the sun), but the bottle immediately exploded. One piece of glass put a 3" long gash along my left cheek and another sliver of glass embedded itself into my right arm just above the elbow.

Pulling the 2" sliver of glass out of my arm (not the most fun thing I've ever had to do) meant that I wasn't aware that blood was running down my left cheek until a mate told me.

I've successfully avoided bottle bombs ever since, but anyone who encounters one has my deepest sympathy!

 

[terrym]

What did you add to the kit? If it's a kilo of dextrose then beersmith says it'll finish at 1.001.

Are you sure? 2kg of LME (my guessed weight of kit) plus 1 kg Dextrose gives OG 1.044 (see OP) at 22 litres start and projected FG 1.011 (Brew UK calculator, Brewers Friend calculator is currently down). This is 74% attenuation which is about right for a kit yeast. 1.044/1.007 is 84%. For OG 1.044, FG 1.001, attenuation is 98% which, for most kit yeasts, is some going!

 

[Drunkula]

Are you sure?

I put 2.1kg in as the kit as I weighed it. I put it into BeerSmith as amber liquid extract which it says has a 1.036 potential and 78% yield. I put in Mangrove Jack's M44 as the yeast. Even without the dextrose BeerSmith says it'll finish at 1.007. Hang on... there are two versions of M44 in there, one with 73% and another with 81% attenuation. One gives 1.003, the other 1.005. Sometimes BeerSmith is a mess. Some things were in there as sugars which it classes as entirely fermentable which I had to change.

 

[Sandimas]

Might be worth double-checking your hydrometer: drop it into water and it should read 1.000. I've never had a beer go lower than 1.008, in 170 brews with all different types of yeast. Cider yes, but not beer. I really can't believe it's 1.002 and you've got 95% attenuation out of a yeast, the best I've managed is 83% with a high-attenuating Belgian yeast. Something is not right here.