Bottle Bomb Calculator | Predict Explosion Risk Before Bottling Beer & Cider

🍾 BottleBombPredictor

Residual Sugar & Over-Carbonation Risk Analyzer

🍯 Final Gravity (FG)

? Specific gravity before bottling. Higher FG = more residual sugar = higher bomb risk. Example: 1.015

🍇 Original Gravity (OG) – optional

? Improves ABV & residual sugar accuracy. If unknown, we estimate based on typical attenuation.

⏱️ Time at stable gravity (days)

? Days since gravity reading stopped changing. Less than 3 days = very risky. Yeast may be dormant, not finished.

🍯 Fermentables added at bottling

? Extra sugars beyond priming. Honey & fruit puree are unpredictable and raise bomb risk significantly.

None (only priming sugar if any — assume standard) Corn sugar (fully fermentable) Honey (70–95% fermentable) Fruit puree / juice (high risk, unpredictable)

🍬 Priming sugar amount (per 5 gallons)

? More priming sugar = higher pressure. Standard is ~3/4 cup corn sugar. Double priming increases explosion risk.

None / already carbonated Standard priming (3/4 cup corn sugar or equiv) Double priming (1.5 cups) – high risk Custom / heavy handed

🧪 Yeast strain

? Wine/champagne yeast ferment more sugars and increase bomb risk. Lager yeast is slower.

Ale yeast (Saccharomyces cerevisiae) – baseline Lager yeast (slower, slightly lower risk) Wine / champagne yeast (high attenuation, higher risk) Wild/Brettanomyces (extreme risk, months active)

🧪 Chemical stabilizers used?

? Potassium sorbate + Campden (metabisulfite) stops yeast reproduction. Dramatically reduces bottle bomb risk.

No stabilizers (highest risk) Potassium sorbate only Sorbate + Campden (metabisulfite)

🍾 Bottle type

? Standard bottles explode at ~4.5 volumes CO₂. Champagne bottles handle higher pressure.

Standard beer bottle (4.0–4.5 vol limit) Champagne bottle (6–7 vol limit) PET plastic bottle (bursts, no glass shrapnel) Swing-top / Grolsch (similar to standard)

🌡️ Current beer temperature

? Warmer temps accelerate yeast activity. Cold crashing (34°F) can delay explosions.

°F

°C

Click "Calculate Bomb Risk" to see detailed analysis.

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⚠️ Disclaimer: This calculator provides risk estimates. Always use proper safety equipment. When in doubt, keg or use non-fermentable sweeteners.

📘 BottleBombPredictor: Complete Guide

How to Use the Calculator

Using the BottleBombPredictor takes less than 60 seconds. Follow these steps:

1. Enter your Final Gravity (FG) — the specific gravity reading just before bottling.
2. Input how many days your gravity has remained stable (unchanged).
3. Select any fermentables added at bottling (corn sugar, honey, fruit puree, or none).
4. Choose priming sugar amount per 5 gallons (standard, double, custom, or none).
5. Pick your yeast strain (ale, lager, wine/champagne, or wild/Brett).
6. Indicate if you used chemical stabilizers (potassium sorbate and/or Campden).
7. Select your bottle type (standard, champagne, PET plastic, swing-top).
8. Set the current beer temperature (°F/°C toggle available).
9. Click “Calculate Bomb Risk & Timeline”.

📌 The tool instantly returns: residual sugar points, 0–100% risk score, recommended action, pasteurization method, safe alternative, and the explosion timeline (e.g., “bottles will explode in 6–9 days at 70°F”).

Why It Matters

Standard priming calculators assume fermentation is complete. They don’t warn you when fermentation secretly restarts due to residual honey, fruit sugars, bottling too early, or wild yeast. Every year, homebrewers face bottle bombs — some causing serious injury (glass shrapnel, deep cuts, eye damage).

This calculator is the only tool that actively detects unstable gravity, risky fermentables, and yeast activity potential. It gives you a practical explosion forecast, pasteurization instructions, and emergency protocols. Whether you brew beer, cider, or mead, the BottleBombPredictor saves batches, equipment, and safety.

The Math Behind the Risk

The calculator converts your FG into gravity points of residual fermentable sugar:

Residual points = (FG – 1.000) × 1000 – 2.5 (non-fermentable baseline)

Example: FG 1.015 → (0.015 × 1000) = 15 total points, minus 2.5 = 12.5 fermentable points (very risky).

Then the tool applies weighted risk modifiers:

• Stability: <3 days stable → +30% risk
• Added honey: +28% risk | Fruit puree: +35% risk
• Wine/champagne yeast: +20% risk | Wild yeast: +35%
• Temperature >75°F: +20% risk
• Chemical stabilizers: –40% to –70% risk (sorbate + Campden)
• High ABV (>12%): –30% risk (alcohol inhibits yeast)

The explosion timeline estimates daily CO₂ production based on total sugar load and temperature, then calculates days until pressure exceeds a standard bottle’s limit (~4.5 volumes CO₂). For example: 1.015 FG + honey + 70°F → ~6–9 days to explosion.

Frequently Asked Questions

Can I still bottle if the risk is high (≥70%)?

Only into champagne bottles (higher pressure rating) or PET plastic bottles (they burst without shrapnel). Always store inside a plastic tub or cooler. Best alternative: keg or wait 7–10 days and re-check gravity.

Does cold crashing stop bottle bombs?

Cold crashing (34°F) slows yeast dramatically but doesn’t kill it. It can delay explosions by weeks, but once the beer warms up, fermentation can restart. For absolute safety, use chemical stabilizers or pasteurize.

What if I already bottled and the calculator shows high risk?

Refrigerate immediately to 34°F for 48 hours. Then carefully open a test bottle outdoors wearing gloves and eye protection. If it gushes violently, open all remaining bottles outside or discard them safely.

Does fruit puree always cause bombs?

Not always, but fruit contains fructose and often wild microbes. Even if gravity seems stable, fruit can restart fermentation weeks later. Always stabilize (sorbate + metabisulfite) or pasteurize when adding fruit before bottling.

How accurate is the explosion timeline?

It’s an estimate based on brewing science (yeast activity Q₁₀, sugar-to-CO₂ conversion). Actual results vary with bottle storage, yeast health, and sugar distribution. Always treat the timeline as a warning, not an absolute guarantee.

Real-World Example

Batch: FG 1.018, stable for 2 days, added 1 cup honey, ale yeast, no stabilizers, standard bottle, 74°F.

Calculation: Residual points = (1.018-1.000)×1000 – 2.5 = 15.5 pts → base risk 40%. Stability: +30%, honey: +28%, temperature: +10%, total = 89% risk. Explosion timeline: ~6 days at 74°F. Recommendation: Do NOT bottle. Wait 7+ days.

Back to Calculator

⚠️ Always wear eye protection when handling suspicious bottles. This guide is for educational purposes.

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⚙️ Mash Efficiency Calculator | Diagnose Low Gravity & Fix Your Brew Day →

Missing your OG by 10+ points? This pinpoints if it's crush, pH, temp, or sparge technique — then tells you how to fix it.

🍬 Priming Sugar Calculator | CO₂ Volumes by Beer Style – No Bottle Bombs →

British ale needs 1.5-2.0 vol, Hefeweizen needs 3.0+ — use the wrong amount and you get flat beer or glass shrapnel. Get exact grams by style.

📊 Homebrew ABV Calculator: Alcohol & Calories →

Don't rely on a rough estimate. Enter OG + FG → get precise ABV, calories per pint, and apparent attenuation. (Works for cider and wine too.)

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Bookmark this page and use them before every brew day.

📚 Scientific & Technical References

Peer-reviewed sources and international standards validating the calculations in BottleBombPredictor.

[1] Teague Jr., J.M. (1953). An investigation of stresses in glass bottles under internal hydrostatic pressure. PhD dissertation. Ohio State University.

OhioLINK ETDC

Validates: Standard beer bottle burst pressure (~200-396 psi), bottle weight correlation with failure pressure, and the empirical basis for explosion threshold calculations.

[2] Fernandes, P.M.B. (2005). "How does yeast respond to pressure?" Brazilian Journal of Medical and Biological Research, 38(8), pp. 1239-1245.

DOI: 10.1590/S0100-879X2005000800012

Validates: Yeast survival under carbonation pressure (cells unaffected below 50 MPa), barotolerance adaptation, and the biological basis for why cold crashing does NOT kill yeast.

[3] Standardization Administration of China. (2005). GB4544-2005: Beer bottles. National Standard of the People's Republic of China.

MISA Glass (industry summary)

Validates: International bottle pressure standards (China 174 psi, developed countries 232 psi, Japan 261 psi, US non-refillable 200 psi) and the finding that recycled bottles are ~25% weaker.

🔬 How These Sources Validate BottleBombPredictor

Teague (1953)

Bottle burst pressure data (200-600 psi)

Fernandes (2005)

Yeast survival under pressure → no spontaneous death

GB4544 Standard

International bottle pressure limits & recycled bottle risk

⚠️ Disclaimer: This calculator provides risk estimates based on published scientific data. Actual bottle failure depends on manufacturing quality, handling, and individual bottle condition. Always use proper safety equipment.