Sometimes homebrew can be a most unco-operative creature.
The beer I have in the fermenter under the stairs hasn’t been doing what it’s supposed to at all. See, it’s a double IPA with a whopping (well, it’s a lot for me) 5kg of fermentables. So I was expecting a pretty hefty starting gravity – like about the 1065 the recipe I was following suggested.
But no, it clocked in at an even 1050. Which made me wonder if filling the fermenter to 20 litres instead of 19 made some sort of difference.
Then a few days ago, the gravity hit 1022 – and has stayed there ever since. Which is about 10 points lower than than
I’d expected. I agitated the fermenter (by which I mean I gave it a shake, not made it nervous and stressed) and even added a spare yeast sachet I had in the fridge.
But nothing happened – it stayed firmly at 1022.
My latest homebrew seems destined for plastic bottles like these.
So now this brew – called Hopless Cause (a name which now seems more appropriate than ever) – is a candidate for the plastic bottles. Just in case it tries for a sneaky ferment later and I get bottles that start going kabloeey.
I know there’s a chance the beer will still turn out fine – I had a stout that started at the same gravity but actually finished eight points higher. That one was quite drinkable. But still, I’d like to know what went wrong because I was trying to get a brew to push past the mystical 5 per cent alcohol barrier.
I’ve only had one beer go past that mark – but that was a full wort kit and so I don’t really count that.
Next time I’m brewing a West Coast IPA clone – and I’m gonna chuck in two sachets of yeast at the start. And only fill the fermenter to the 19-litre mark.
And then I’m going to agitate the fermenter. And this time I do mean that I will make it nervous and stressed – ‘‘if you don’t make good beer higher than 5 per cent, I’m swapping you for one of those other fermenters in the garage’’.
Categories: brewery, exploding beers, homebrew
BEER IS YOUR FRIEND 
so its an all extract brew? if so I’d just give it another week or so, perhaps ramp the tempreature up a bit and shake it once a day. At a starting gravity of 1050 in 20 litres a pack of dry yeast should do the job. Oh and adding more water will reduce the gravity, get some brew software like brew smith and you can check it out.
No, its extract with 1kg of grain. Can’t work out why it didn’t start higher. Anyway, I’m likely to give it until Tuesday to see what happens (that’ll be a week from the 1022 reading). If nothing changes, it’s getting bottled.
what was the 1 kg of grain? that could have given you some unfermentables depending on what the grain was and how you treated it (i.e. how did you mash it and would that change it anyway).
The second yeast probably didnt do a whole lot and if it did it would need to go through a lag phase and growth stage before it started anyway.
How does it taste?
grain was half caramalt and half amber, crushed and mashed at about 64 degrees for 45 minutes. It tastes okay, mainly hoppy but with a bit of sweetness. Perhaps that’s from the unfermented sugar?
not 100% familiar with those malts but thats a lot of character malt that may not convert its self – some crystal lacks enzymes (or is at least low in them) and some of the sugars in these malts may not convert at all. I think this is the issue – and the sweetness is unfermentable sugar.
I’d think about holding back on the crystal additions in the future
Hmmm, you should get a higher SG with that much sugar. Any chance that it didn’t all disolve/mix properly? Or that the temp was very high? You need to adjust your gravity readings if the temp is significantly different than the calibration temp of your hydrometer – calibration should be printed on the scale (usually 20C) and Google will find the calcs for you. The extra litre will only change it by 1/19th, so about 5% ie 1.062.
As for the stuck fermentation it gets very technical but adding more yeast often will not help as there is no dissolved oxygen in your beer, so it cannot enter the respiritory phase needed to multiply before entering the fermentation phase. Introducing more oxygen at this stage can have other unwanted effects but it is fairly necessary, thus the agitation. This is a topic that even my brewing lecturer was unable to give definite answers to, making the yeast exam quite challenging.
Another main cause of stuck fermentation is running out of zinc, which is a co-factor required for the yeast to convert acetaldehyde into alcohol, the final step of fermentation. If you can taste green/bruised apple in the beer this is probably what has happened. It can happen when you use a lot of adjuncts, as other sugar sources (esp refined ones) do not have the high levels of nutrients that come from malt. Yeast nutrient from a homebrew shop has plenty of zinc and a few other goodies – I always use it with extract brews.
Goodluck
Hadn’t heard anything about needing to adjust a gravity reading based on the temp of the fermenter. Think it was fermenting at about 22-23 degrees for the most part.
Good to know that the brewing teacher couldn’t give a definitive answer – makes me think there’s just as much guesswork as science in homebrewing.
The ingredients were 3.4kg LME, 500g DME and 1kg of grain. There’s no green apple flavour that I can detect. I’m going to monitor it for a few more days and if the gravity doesn’t change, I’m bottling it and crossing my fingers.
Yep, sounds like just lots of unfermentables like Koongara said, which is sort of the point with cara/crystal malt. The amber probably had enzymes (unless it was cara/crystal amber) thus requiring mashing – crystal malt doesn’t need to mash as starch conversion has already completed vis “stewing” at the malting house. Either way 1kg is a fiar bit and if the mash wasn’t succesful would leave high levels of unfermentables, but that doesn’t explain the low SG of 1.050. A few degrees makes very little diff to the calibration but if you used a lot of boiling water and took your reading at >30C it can be a few points out – basically liquid is less viscous when hot and a hydrometer just measures viscousity/density.
The plastic bottles are a good idea, but it would be worth throwing in some fresh yeast with yeast nutrient and agitating like crazy.
NB My brewing lecturer was previously head brewer at XXXX and Swan and is an industrial chemist, so he’s troubleshooted (shot?) a lot of fermentation problems in his time. Even with an indepth knowledge of chemistry and commercial brewing he still gets stumped sometimes.
yep the temp does influence the SG but if your about 20ish it should be close enough. As for more yeast or not, you dont actually know how much there is left to ferment but you do know that the yeast you used did work so dont worry about adding more. Just give it some more agitation and time, then relax and bottle it, may not be the best beer you ever make but it’ll be ok, just a bit full or heavy
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