Cleaning uses a cleaner, soaking, and mechanical action to remove grime and residue from your equipment. Sanitising uses a sanitising agent to kill most bacteria at a microscopic level. You cannot sanitise effectively if you are not starting from a clean surface.

People often say “sterilise” when they mean sanitise.

As long as it takes to finish fermenting. Your hydrometer tells you when fermentation is done.

Wait until bubbling has slowed or stopped, then take a hydrometer reading. Wait 24–48 hours and take another. If both readings match, sugar level is stable and fermentation is finished—unless the fermenter is too cold, because cold can make yeast go dormant and fermentation can pick up again when the temperature rises.

The hydrometer is one of the most useful tools for brewing. It measures specific gravity (S.G.)—the density of sugars in your liquid.

Take a sample in a test flask and float the hydrometer to read S.G. Water is 1.000 at the meniscus at 20 °C. Before you pitch yeast, your reading is your original gravity (O.G.). More sugar makes the liquid more buoyant, so the hydrometer sits higher.

During fermentation, yeast converts sugar to alcohol. After a week or so you should see the reading fall. Alcohol is lighter than water, and remaining sugars are less concentrated, so the hydrometer sinks closer toward 1.000 (not usually all the way).

Use final gravity (F.G.)—the point where yeast can no longer ferment more sugars—to know when you can safely bottle. At that stage the yeast is not still chewing through wort sugars, apart from what you add for priming (for example carbonation drops) for bottle conditioning.

Use:

ABV = (OG − FG) × 131

Example: (1.045 − 1.010) = 0.035 × 131 ≈ 4.56% ABV.

Sometimes the wort really is very high in sugar. Often, though, the sample is misleading: if you drew from the tap at the bottom of the fermenter, dense sugars can settle low and inflate the reading.

Airlock bubbling is just gas leaving the fermenter. Some yeasts work slowly—match slow bubbles to gravity changes with your hydrometer.

Temperature swings matter too: liquid holds more gas when cold. Slow bubbles after fermentation can be the beer releasing dissolved CO₂ as it warms.

Vigorous fermentation—and yeast strain plus headspace versus liquid volume—can push krausen into the airlock. Messy, but not uncommon.

Swap in a blow-off tube: wide tubing from the bung into a sanitiser-filled vessel sitting below the fermenter liquid level (clean and sanitise everything first).

German wheat, Belgian wit, and some English strains often want roughly one-third fermenter headspace (for example ~20–21 L in a 30 L fermenter). Higher-gravity beers mean more yeast activity and more chance of foam escaping.

In bottle-conditioned beer, sediment is mostly yeast and precipitated proteins—similar to trub at the end of fermentation.

The yeast eats priming sugar, produces a little alcohol and CO₂ for carbonation, then settles. Cold conditioning compacts sediment; pour carefully into a glass if you prefer it clear (the sediment is safe—some brewers drink it for B vitamins).

Carbonation drops are a measured dose of sugar for yeast to ferment in the bottle. CO₂ dissolves and gives you fizz.

Typical dosing: one drop per 330–375 ml bottle, two per 750 ml—follow what your supplier recommends for your bottles.

Often it is bottling before primary fermentation has truly finished: yeast keeps eating leftover sugars plus priming sugar, so excess CO₂ builds up. Opening can gush; worst case, bottles can fail.

Confirm stable final gravity over a couple of days at fermentation temperature before bottling.

Over-carbonation can also come from infection with wild yeast or bacteria—watch for flavour changes versus bottling day. Tighten up cleaning and sanitising, and make sure gear from older batches is fully cleaned.

Heavy amber beer bottles are ideal. Green or clear lets light strike hops and can cause “skunky” character—think dusty green imports left in bright display.

Amber blocks the wavelengths that cause that reaction.

Hops are a climbing plant that produces cone-like flowers. Inside those cones are resins and oils that brewers use mainly for bitterness, aroma, and stability.

After harvest, hops are dried and usually compressed into pellets for storage and brewing.

That sulphur note is often sulphur compounds from yeast—more common with some lager strains—and can linger lightly to support a crisp profile.

If you can smell it leaving the fermenter, it is usually off-gassing as intended. With lagers, give the beer time at the end of fermentation to clean up; taste and smell your hydrometer sample before packaging.