Fermentation seems to be stuck at 1.022 after 2 1/2 weeks

Question

This my absolutely first time brewing beer. I'm excited to try brewing my own and experimenting with flavours etc.

I bought a kit from a from a brew store which included a fermenter and everything I thought I'd need. I asked for the recipe for a Leffe Blonde.

So after careful sanitising, I mixed all of the ingredients in the fermenter together, and pitched the yeast. The wort temperature at this stage was 24C/75F. I measured the gravity then, and it was 1.052

It's pretty cold where I am in Sydney now, and after a couple of nights, the fermenter temp dropped to about 16C/61F. I ended up buying a heat pad and temperature controller to keep the fermenter temp between 19-20C/66-68F.

After 4 days the bubbling in the airlock stopped, I measured the gravity at 1.022.

I measured a week later and the gravity hasn't changed. It will now be 3 weeks on Sunday and the gravity still hasn't changed. It tastes a little like beer but quite sweet and yeasty, and it doesn't look like the yeast has flocculated and is still suspended in the wort.

What could be going on, have I somehow got a stuck fermentation? Should I just have some more patience and leave it longer? There is no Krausen on the top of the beer and it seems that the yeast in the kit was an S-33. I don't know what other information to provide...

Any help would be greatly appreciated :)

Answer 1

You probably have a stuck fermentation, if it is not tasting bad then that is good news.

I would open it up and pitch a fresh starter of made up with some new S33.

How to make a starter: https://www.youtube.com/watch?v=jMhFerNTwbQ

Answer 2

I assume this is an extract beer? Extracts often have a high amount of unfermentables which can lead to this situation. It would help if we knew the recipe. If that's the case, you can add al the yeast in the world and it won't do any good. Given an OG of 1.052, the S33 should have been able to chew through it if the wort was fermentable enough.

Answer 3

I wouldn't pay too much attention to the folks saying "extract comes out high due to extra unfermentables". In my experience, it's just not true, and even if it was, that's clearly not your problem here, because you say that the wort tastes sweeter than it should (unfermetable sugars don't actually taste very sweet. If you're getting sweetness, it's because there's fermentable sugars still in there that the yeast just haven't processed for some reason).

As Mr_road mentioned, this sounds like a classic stuck fermentation. This can happen for all kinds of reasons (some of which aren't well understood even by the experts), but substantial temperature changes can definitely make things like this more likely.

The best way to try to fix this is to get yourself some new, fresh yeast, rehydrate it according to the manufacturer's instructions, then make up a starter to get it nice and active before pitching it into your fermentor. Note that many instructions for making starters tell you to let it run until the yeast has fully used up all the nutrients (12-24 hours) and falls out of solution, which is good if you're doing an initial pitch, but is not what you want for restarting a stuck brew. In this case, you want to toss the yeast in when they're at their most active, and you've got lots of bubbles going (usually about 4-8 hours in).

Along with the new yeast, you may also want to add a good wide-spectrum yeast supplement like Fermaid K to make sure both the old and new yeast have all the nutrients they might want to really take off (my local homebrew supplier sells this in individual 8g packets, which are more than enough for a 5 gallon brew, and they keep for a pretty long time, so I always keep one or two around just in case). When the starter is nice and active, measure out an appropriate amount of the supplement for your batch size, mix it in with the starter, and pitch the whole thing in (Note: don't add the supplement to the beginning of the starter, as this will be way too much for the size of the starter and will create a stressful environment for the yeast. Mix it in just before you pour the whole thing into the larger batch, so the nutrients will be diluted out the right concentrations in the fermentor).

If you don't feel up to making a starter (which isn't that hard, but I know can be a bit intimidating to those who haven't tried it before), you can still do all this without it: Rehydrate your yeast, and then mix it and the supplement in enough sterilized water to make sure everything's nicely dissolved, and then pitch it directly in. In this case, you might want to use a double-portion of yeast to give it a bit more of a head start..