Home Brewing Troubleshooting — Common Problems and How to Fix Them

Why has my home brew fermentation not started?

If there's no airlock activity after 48 hours, the most common cause is temperature — below 15°C and most yeasts are inactive. Move to a warmer location (18–24°C is ideal). Also check the lid is sealed and the airlock is correctly filled with water. If temperature isn't the issue, pitch a fresh sachet of Gervin GV12 Ale Yeast or use GV7 Restart Yeast to get a stuck fermentation going. See our full home brew FAQ for fermentation questions.

Why is my home brew beer cloudy?

Cloudiness is usually caused by yeast still in suspension, protein haze, or chill haze. Add Young's Beer Finings 48 hours before bottling, then cold crash (cool to 2–4°C for 48 hours) if possible. Using Protafloc Tablets in the boil prevents protein haze from forming. Ensure fermentation is fully complete before bottling — residual activity causes persistent haze.

Why does my home brew taste cidery or of apples?

A cidery or green-apple flavour is acetaldehyde — a fermentation byproduct the yeast cleans up given enough time. It means the beer was bottled too early, fermented too warm, or used too much plain white sugar. Ferment for a full 14 days, replace plain sugar with Brew Enhancer 2, and condition in the bottle for at least 3 weeks. Read our Brew Enhancer guide for more on the cidery sugar problem.

Why is my bottled home brew flat?

Flat bottles are caused by insufficient priming sugar, bottles not sealed properly, or fermentation incomplete at bottling. Use one Carbonation Drop per 500ml bottle, check all crown caps are fully crimped, and always confirm fermentation is done with a hydrometer before bottling. Store at room temperature for at least 14 days before cooling. See our conditioning guide for timing. Browse our full range of brewing additives at BrewCo UK.