Common homebrew problems and how to fix them

Something has gone wrong and you want to know whether it's saveable

Everybody who brews has opened a bottle they'd been waiting weeks for and found it flat, or cloudy, or tasting of something that was never meant to be in there, and the first thing that goes through your head is that you've wasted the whole batch. Usually you haven't. Most of what goes wrong in a homebrew is either fixable with time or fixable next time, and knowing which of those two you're looking at is most of the battle.

It tastes like wet cardboard

That papery, stale flavour is oxidation, and it happens when air gets to the beer after fermentation has finished rather than before it. The damage is already done by the time you taste it, so there's no fixing the batch in front of you, but it's one of the easiest faults to design out. Be gentle when you transfer, keep the splashing down, and stop opening the fermenter to have a look at it, because every look costs you something.

It's flat

Flat beer is nearly always either not enough priming sugar or not enough warmth, and both of those are recoverable. Give the bottles more time somewhere warm before you write them off, because carbonation can take a couple of weeks and a cold shed will stretch that out a long way. The instructions with your kit give the temperature range it wants and that's the number I'd work to rather than a figure off a blog.

The other direction matters too. Too much priming sugar makes bottles that gush, and at the far end it makes bottles that break, so measure it rather than eyeing it off.

It's cloudy

Some styles are meant to be cloudy and a wheat beer is doing what it's supposed to, so the first question is whether you've actually got a problem. If a lager or a pale ale has come out murky, cold is the simplest answer, because a few days chilled will drop a lot of haze out on its own. Finings will do the rest if you want it properly bright, and giving the beer time to clear before you bottle it is what stops the question coming up at all.

It smells of nail polish remover

That solvent smell points at a fermentation that ran too warm, or at something growing in there that shouldn't be. A mild one often mellows with a few more weeks in the bottle. A strong one does not, and that batch is a lesson rather than a beer. The prevention is the boring half of brewing, which is keeping the fermenter somewhere the temperature doesn't swing, and sanitising properly rather than rinsing and hoping.

It smells of rotten eggs

Sulphur is alarming and it's usually nothing. Plenty of yeast strains throw it while they're working and it fades on its own, so leave it another week or two and smell it again before you panic. If it's still there after conditioning, look at your yeast choice for next time rather than at the batch.

It's too sweet, or it's too dry

Sweet usually means fermentation stalled before it was finished, and dry means the yeast got further through the sugars than you expected. A hydrometer settles which one you've got, and it's the single most useful thing you can have on the bench because it turns a guess into a reading. If it has stalled, warming the fermenter a little and giving it a gentle swirl will often get it going again.

It tastes fruity and you didn't want it to

Fruity esters belong in some styles and are a fault in others, and they come from fermenting warm. If it's mild, time in the bottle takes the edge off. If it's not, the fix is a stable fermentation temperature next time, matched to what your yeast actually wants rather than to whatever the shed is doing that week.

The pattern underneath all of it

Look back over that list and nearly every fault traces to one of two things, which is temperature or sanitation. Get those two right and the rest of brewing is fairly forgiving, which I think is why so many people who try it once end up still doing it years later.

Shop related products

• Coopers Brew Enhancer 1 1kg. This gives a kit beer more body than plain sugar does.
• Coopers Dextrose 1kg. Use this for priming and for the fermentables in a light beer.
• Coopers Light Malt Extract 1.5kg. It builds body and head retention if your beer is coming out thin.
• Coopers Original Draught 1.7kg. This is a forgiving kit if you want a clean batch after a bad one.

Did you know we also hold hydrometers and test jars, glass thermometers, no rinse sanitiser, finings and heater belts in the shop that never make it onto the website. Give us a ring on (08) 8536 4333 to check what's on the shelf.

Where to go next

The beer supplies and the wider homebrew range cover most of what you'll want, and Brewhilder is there if you'd rather describe the problem to something than read a list.

Worth reading next: How to brew your first beer at home and 7 reasons to brew your own beer at home.

I'm the one who swears the fermenter is fine and never thinks to check what the shed is doing.