fermentation finishing too high

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Brewed for the first time on a new system at the weekend. All went reasonably smoothly except the mash temp was very erratic dropping 10 degrees initially then shooting up to well into the 70 degrees C. Fermentation kicked off as normal using Verdant yeast but is tapering off and looks to be finishing at around 1,030 (from an OG of 1.055). I don't think its a stuck fermentation as such but maybe just produced way too much non fermentable sugars. Is there anything I can do to recover the beer? obviously its going to finish quite sweet, though I still need to dry hop, and very low in ABV. I thought I could drop in some sugar to boost ABV but that wont do anything about the non-fermentable sugars.

Thanks.
 
That's going to give you 3½ % abv and I think you were looking for something stronger than that. it's also going to be cloyingly sweet. If it were me, I'd hope for a stuck fermentation and try rousing the yeast by stirring it all back up into the wort, quite vigorousy.
If that didn't work I'd add some amyloglucosidase or whetever they call saccharifying enzymes these days. This will work and it won't taint your beer, but you'll end up with a LOWER FG than you intended.
Alternatively you could ferret through your yeast collection and look for one- possibly a saison or perhaps a likely Belgian strain, but go through the yeast specs and look for one which has the STA 1 gene positive (although it could be 2 or 3 as well). Repitch with this yeast and it should sort you out eventually, but this would be much slower than simply adding amylase.
 
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It's only been fermenting a few days. Leave it be - fermentation often takes 1-2 weeks.

It's often hard to tell whether it's still fermenting or not. No harm will come to leaving it to ferment for longer. I am guilty of worrying unnecessarily early about fermentation and bottling too early when the gravity is too high and on reflection it was obviously still fermenting - it went into the bottles like pond water and was hugely overcarbed.

If it truly is a stuck fermentation, then rousing the yeast can apparently help (though I've never had it do so) - try to swirl the fermenter without taking the lid off in case you introduce too much oxygen and spoil it. Raising the temperature can also help, but in a current heatwave I assume it's already quite warm.

... it's also going to be cloyingly sweet.
If the cause of the low attenuation residual unfermentable sugars, then I dispute that it makes cloyingly sweet beer. I have had quite a few beers that (for whatever reason) have finished up at around 1.020 (from ~1.045-1.050 OG), and none of them tasted sweet. (Also see Brulosophy experiments on the same topic). As I understand it, the reason for this is as follows:
  1. Mashing at a high temperature means it's predominantly the alpha-amylase that's active
  2. Alpha amylase produces higher quantities of long-chain sugars (Dextrins, Maltotriose etc) when compared to the maltose produced
  3. The yeast ferments away the maltose, but not the dextrins/maltotriose
  4. Maltotriose only tastes 30% as sweet as sucrose
  5. Dextrins don't taste very sweet
  6. Neither does maltodextrin
  7. So the only unfermented sugars left in the beer don't taste particularly sweet.
This has certainly been my experience, but your taste may be different (espeacially for those people who love to hate Brulosophy 😂)
 
Also, dry hopping tends to allow for increased fermentation (which is probably beneficial for you since you intend to dry hop). Google 'hop creep'. I am guessing, but I am imagining that the hops contain additional enzymes that break down some of the longer-chain sugars, that then get fermented out.

This page says:
To delve a little deeper into the biochemistry, evidence strongly suggests that hops carry amylolytic (AKA starch-degrading) enzymes that convert long-chain, unfermentable dextrins into fermentable sugars. These enzymes likely become inert when subjected to a boil. But when they’re added to unpasteurized beer on the cold side, it’s believed that any live yeast that remains in suspension acts on those sugars to cause a gradual secondary fermentation.
 
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the reason why I think it's topping out rather than stuck is that I've used verdant many times before and find it to be a very fast fermenter for me...almost like kveik..kicks off within 24 hrs and is normally pretty much done by day 4. I'm at day 3 and the fermentation is tapering off rather than suddenly stopped or stalled...and given the trend it will have topped (or bottomed) out within the next 24hrs.

However advice about assuming a stuck fermentation is far and might be worth a blast up the dump valve to rouse the trub. I'll give it a few more days to confirm it is finishing/stalling.

I don't have any saison or Belgian yeasts in stock but can probably get some pretty quick or the enzymes but will have to satisfy myself its not a stuck ferment before using.

What about adding sugar to boost ABV? was aiming for 4.5 to 5 ish for an up and coming party. Normally wouldn't be bothered about a lower ABV beer, I'd just let it ride. can I try the yeast or enzyme pitch first and if that doesn't work add sugar or do I need to add sugar before fermentation has completed?
 
There's no hurry to add sugar. You can add it at the very end when fermentation has finished and it'll come back to life and ferment the sugar (this is exactly what happens for bottle/cask conditioning)
 
It's only been fermenting a few days. Leave it be - fermentation often takes 1-2 weeks.

It's often hard to tell whether it's still fermenting or not. No harm will come to leaving it to ferment for longer. I am guilty of worrying unnecessarily early about fermentation and bottling too early when the gravity is too high and on reflection it was obviously still fermenting - it went into the bottles like pond water and was hugely overcarbed.

If it truly is a stuck fermentation, then rousing the yeast can apparently help (though I've never had it do so) - try to swirl the fermenter without taking the lid off in case you introduce too much oxygen and spoil it. Raising the temperature can also help, but in a current heatwave I assume it's already quite warm.


If the cause of the low attenuation residual unfermentable sugars, then I dispute that it makes cloyingly sweet beer. I have had quite a few beers that (for whatever reason) have finished up at around 1.020 (from ~1.045-1.050 OG), and none of them tasted sweet. (Also see Brulosophy experiments on the same topic). As I understand it, the reason for this is as follows:
  1. Mashing at a high temperature means it's predominantly the alpha-amylase that's active
  2. Alpha amylase produces higher quantities of long-chain sugars (Dextrins, Maltotriose etc) when compared to the maltose produced
  3. The yeast ferments away the maltose, but not the dextrins/maltotriose
  4. Maltotriose only tastes 30% as sweet as sucrose
  5. Dextrins don't taste very sweet
  6. Neither does maltodextrin
  7. So the only unfermented sugars left in the beer don't taste particularly sweet.
This has certainly been my experience, but your taste may be different (espeacially for those people who love to hate Brulosophy 😂)
Quite so. But there's a considerable difference between 1020 and 1030, especially with an OG of 1055. Having said that, I have a particular dislike of sweet beers and I have to be very light handed indeed with any recipe using crystal malt, for example. perhaps there's too much ptyalin in my saliva and I should offer to spit in the OP's beer. That'd sort it out.
Also, dry hopping tends to allow for increased fermentation (which is probably beneficial for you since you intend to dry hop). Google 'hop creep'. I am guessing, but I am imagining that the hops contain additional enzymes that break down some of the longer-chain sugars, that then get fermented out.
That's a good point, but it's a painfully slow process and with a low alcohol beer, I'd be wanting to get it up to strength first. If you're going to add sugar, do that first and then the dry hops.
 
Well I prayed to the brew gods and my prayers were answered. I took a hydrometer reading and my gravity is alot lower than indicated on the iSpindel so after a few days I should be there or there about on my target FG...maybe a couple or few points high so that'll do for me. A bit odd...my iSpindel usually reads five or so points too high at the start of fermentation so I account for that as its a consistent error, but usually reads pretty much bang on at FG, but in this case the iSpindel was reading its usual high reading at the start but nearing finishing it is still reading high in fact higher error than the OG. Maybe my iSpndel could do with re-calibration or maybe it was hung up on something.

Looks like I dodged a bullet considering the swinging temperatures through the mash....Thanks for the advice everyone...good to know anyway for future reference, all great tips.
 

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