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Guide

How to bottle homebrew (and avoid bottle bombs)

How to bottle homebrew step by step: confirm final gravity, weigh priming sugar, fill and cap, condition at room temperature, and avoid bottle bombs.

Updated November 2026 · 7 min read

Freshly filled swing-top bottles beside a glass fermenter on a counter
Photo: mbeldyk, CC BY-SA 2.0, via Flickr
The short version
  • Bottle only when the hydrometer reads the same 2–3 days in a row. Unfinished beer keeps fermenting in the bottle.
  • Weigh priming sugar with a calculator, using the warmest temperature the beer reached after fermentation.
  • Mix the dissolved sugar evenly into the beer in a bottling bucket, not bottle by bottle.
  • Condition about 2 weeks at room temperature in a closed box, then refrigerate.
  • Standard 12 oz pry-off bottles are not meant for more than about 3.0 volumes of CO2.

Knowing how to bottle homebrew well is mostly about two numbers: a stable final gravity and the right weight of priming sugar. Get both right and every bottle carbonates the same; get either wrong and you end up with flat beer or, worse, over-pressured bottles that can burst. This guide gives the full routine for a 5 gal (19 L) batch, which fills about 50 standard 12 oz bottles.

The priming numbers come from the BYO carbonation priming chart and the residual-CO2 formula used by our priming sugar calculator; the process follows Palmer’s How to Brew. Bottle conditioning means the yeast still in the beer eats the priming sugar inside the sealed bottle and makes CO2, which dissolves into the beer.

What you need to bottle a 5 gallon batch

Bottling gear for 5 gal (19 L)

ItemAmountWhy
Bottles, 12 oz pry-offAbout 50 (or about 26 × 22 oz)✓ Heavy brown glass; no twist-offs
Crown capsAbout 55 (a few spares)✓ Oxygen-absorbing caps are optional
CapperWing or bench✓ Bench cappers are easier on long sessions
Bottling bucket with spigot6.5 gal✓ Lets you mix sugar evenly
Auto-siphon and tubing1✓ Moves beer off the yeast without splashing
Spring-tip bottle filler1✓ Fills from the bottom, stops when lifted
Priming sugarWeighed per calculator✓ Corn sugar is the usual choice
Kitchen scaleGrams✓ Volume measures vary too much
Sanitizer and bottle rinser or treeLabel dilution✓ Every bottle, every cap

Source: Palmer, How to Brew; kit listings

Brown bottles lined up next to a white bottling bucket on a kitchen floor
About two cases of bottles for a 5-gallon batch.Photo: Ginkgo100 at English Wikipedia, CC BY-SA 3.0, via Wikimedia Commons

Step 1: make sure fermentation is finished

This is the step that prevents bottle bombs. Take a hydrometer reading, wait 2–3 days, and take another. If both match and the number is near the recipe’s expected final gravity, the yeast is done. If the gravity is still falling, wait. Airlock bubbles stopping is not proof; a leaky lid or a temperature drop can quiet the airlock while sugar remains.

If the gravity is stuck well above the expected number, don’t bottle. Warm the beer a few degrees, swirl gently to rouse the yeast and check again in a few days. See how to use a hydrometer for reading and temperature correction.

How much priming sugar for 5 gallons?

Carbonation is measured in volumes of CO2: how many times the beer’s own volume of gas is dissolved in it. Style families have typical ranges, and the beer already holds some CO2 from fermentation. That residual amount depends on the warmest temperature the beer reached after fermentation (warmer beer holds less), so the calculator subtracts it.

Pouring sugar onto a brass kitchen balance to weigh it
Weigh priming sugar rather than measuring by volume.Photo: Wald1siedel, CC BY-SA 3.0, via Wikimedia Commons

CO2 volumes by style family (bottle or keg)

Style familyVolumes of CO2Bottle-safe?
British ales1.5–2.2✓ standard bottles
American ales2.2–3✓ standard bottles
European lagers2.4–2.6✓ standard bottles
American lagers2.5–2.8✓ standard bottles
Belgian ales2–4.5~ standard bottles only to about 3 vol
German weizen2.8–5.1~ standard bottles only to about 3 vol

Style ranges: BYO: Carbonation priming chart. Standard 12 oz pry-off bottles are not meant for more than about 3.0 volumes. Bottle only after the gravity reads the same 2–3 days in a row.

For a 5 gal batch whose warmest temperature after fermentation was 68°F (20°C), the residual CO2 is about 0.86 volumes. The chart shows the corn sugar needed for common targets.

Corn sugar for 5 gal, warmest temperature 68°F

Grams = (target vol − 0.86) × 5 gal × 16.7 g per gal per vol

2.0 vol (British ales)2.0 vol (British ales): 95 g95 g2.2 vol2.2 vol: 112 g112 g2.5 vol (American ales)2.5 vol (American ales): 137 g137 g2.8 vol2.8 vol: 162 g162 g3.0 vol (bottle limit)3.0 vol (bottle limit): 179 g179 g
Source: BYO carbonation priming chart (sugar factors); residual CO2 formula

Table sugar works too but carbonates a little more per gram, so use less; dry malt extract needs more and is less predictable. The calculator handles corn sugar, anhydrous dextrose, table sugar and a DME estimate.

Priming sugar calculatorEnter volume, warmest temperature and style target; it warns when a target goes above about 3.0 volumes.

Carbonation drops and tablets

Pre-measured drops are convenient for small batches and mixed bottle sizes, but each drop is a fixed amount per bottle, so you can’t fine-tune the level. Follow the maker’s count per bottle size.

Bottling day, step by step

  1. Clean bottles ahead

    Rinse bottles right after pouring commercial or homebrew beer. On bottling day they only need inspection (chips, cracks, residue) and sanitizing.

  2. Sanitize everything that touches beer

    Bottles, caps, bottling bucket, spigot, auto-siphon, tubing and filler, using a no-rinse sanitizer at label dilution. A bottle tree and a rinser speed this up.

    LD Carlson Econo 45 Bottle Drying TreeFastRack Bottle Rinser (Sulphiter)
  3. Dissolve the priming sugar

    Boil the weighed sugar in about 1–2 cups of water for a few minutes, cover and cool. Pour it into the empty bottling bucket.

  4. Siphon the beer onto the sugar

    Let the tubing curl along the bottom of the bucket so the beer swirls in gently without splashing. Leave the yeast cake behind. The flow mixes the sugar; one slow stir with a sanitized spoon at the end evens it out.

  5. Fill each bottle

    Attach the filler to the spigot, press it to the bottle bottom and fill until the beer reaches the top. Removing the filler leaves about an inch of headspace, which is right.

  6. Cap right away

    Place a sanitized cap and crimp it with the capper. Check that the crimp is even all around.

  7. Store warm, in a box

    Keep the bottles at about 68–75°F (20–24°C), in a closed box or tote, out of light. Most ales carbonate in about 2 weeks; bigger beers take longer.

  8. Test one, then chill

    After 2 weeks, chill one bottle for a day and open it. If it is carbonated, move the batch to the fridge, which stops further pressure build-up and helps the yeast settle.

How to avoid bottle bombs

A bottle bomb is a bottle that over-pressurizes and breaks, sometimes violently. The causes are well known, and so are the fixes.

Bottle bomb causes and prevention

CauseWhat happensPrevention
Bottling before final gravityLeftover sugar ferments in the bottle on top of the priming sugar✓ 2–3 identical readings over 2–3 days
Too much priming sugarMore CO2 than the glass is meant to hold✓ Weigh with the calculator; stay ≤ about 3.0 vol in standard bottles
Uneven mixingSome bottles get a pocket of sugar✓ Mix in a bottling bucket, not per bottle
InfectionWild yeast or bacteria eat sugars that brewing yeast can’t✓ Clean and sanitize; watch for gushers
Weak or damaged bottlesThin, chipped or twist-off glass fails first✓ Inspect each bottle; use heavy pry-off glass
Warm storage for monthsPressure rises; any defect shows✓ Refrigerate once carbonated

Source: Palmer, How to Brew; BYO carbonation priming chart

Avoid bottle bombsBottle only after the gravity reads the same 2–3 days in a row, measure priming sugar with a calculator, use standard bottles only to about 3 volumes, store them in a closed box at room temperature and refrigerate once carbonated.Source: BYO carbonation priming chart
Glass carboys breakGlass carboys can break and cut. Use a good carboy handle and always support the bottom when you move a full one; a crate or carrier under the base helps on slippery floors. Never pour hot wort into cold glass. PET and stainless avoid the risk.Source: Craft Beer & Brewing: Homebrew safety

If you suspect over-carbonation (gushing when opened, bulging caps), move the whole batch into a fridge inside a closed container, wearing eye protection and gloves, and open bottles over a sink pointed away from you. Never store bottles where they could injure someone if they broke.

Swing-tops, bombers and other bottles

Swing-top bottles skip the capper. Check the rubber gaskets each time and replace them when they crack or flatten. Larger bottles (22 oz bombers, 500 mL, 750 mL) mean fewer to fill and cap. Belgian-style bottles for very high carbonation must be rated for it by the maker; standard American bottles are not.

A shelf of amber and green swing-top bottles backlit in a window
Swing-top bottles reseal without a capper.Photo: AlfvanBeem, CC0 1.0, via Wikimedia Commons

Mistakes to avoid

  • Bottling on a schedule instead of on a reading. The hydrometer decides.
  • Measuring sugar by volume. Cups and scoops vary; weigh in grams.
  • Using the fermentation temperature you set instead of the warmest the beer reached. It changes the residual CO2.
  • Adding sugar to each bottle by hand. Uneven doses are the classic route to a few bombs in a batch.
  • Splashing beer during transfer. Oxygen causes cardboard staleness within weeks.
  • Refrigerating too early. Cold yeast stops working and the beer stays flat; condition warm first.
  • Using twist-off or chipped bottles. They leak or fail.

Bottling or kegging?

Bottles are the cheapest packaging, travel well and age well. Kegging carbonates in days and replaces 50 bottles with one vessel, but costs more up front and needs CO2. Many brewers keg most batches and bottle a few for sharing. Read how to keg homebrew and the background in carbonation explained.

Before you share, use the ABV calculator to know the strength; bottle conditioning adds a small amount of alcohol from the priming sugar. Serve only to adults 21+, and never drink and drive.

Gear picks for this guide: best bottle cappers and best hydrometers for homebrewing.

VerdictBottle on a stable reading, weigh priming sugar with the calculator, mix it evenly in a bottling bucket and condition warm in a closed box. Those four habits deliver even carbonation and keep bottle bombs off the table.
ABV calculatorWork out ABV from OG and FG with the standard and high-gravity formulas, hydrometer temperature correction,…Priming sugar calculatorHow much corn sugar, table sugar or DME to prime homebrew: CO2 volumes by style, residual CO2 from the…

Questions

How much priming sugar for 5 gallons?
For a typical American ale at 2.5 volumes, with the beer’s warmest temperature at 68°F, about 137 g (4.8 oz) of corn sugar. Use the priming sugar calculator for your style and temperature.
How long does it take to bottle condition homebrew?
About 2 weeks at 68–75°F (20–24°C) for most ales. Strong or cold-conditioned beers can take 3–4 weeks. Chill one test bottle before moving the batch to the fridge.
Can homebrew bottles explode?
Yes, if the beer is bottled before fermentation is finished, with too much priming sugar, with an infection, or in weak bottles. Stable gravity readings and a priming calculator prevent almost all cases.
Can I reuse commercial beer bottles?
Yes, standard pry-off bottles in good condition. Avoid twist-off bottles, which don’t seal reliably with a standard capper.
Do I need to boil priming sugar?
Boiling it briefly in a little water dissolves it fully and sanitizes the solution. Cool it before adding the beer.
Why is my bottled beer flat?
Usually it is too cold, too young or under-primed. Move the bottles to about 70°F and wait another week. Very old or high-alcohol beers may need fresh yeast at bottling.
Can I use table sugar to prime beer?
Yes. Table sugar (sucrose) carbonates slightly more per gram than corn sugar, so use a little less; the calculator adjusts for it.

Sources

  1. BYO: Carbonation priming chart
  2. John Palmer, How to Brew (priming and bottling)
  3. AHA: How to take an accurate hydrometer reading
  4. American Homebrewers Association: How to brew
  5. Craft Beer & Brewing: Homebrew safety
  6. NIAAA: What is a standard drink?