This Pre-Prohibition Porter all-grain recipe is designed as a complete 23 L formulation at 75% brewhouse efficiency. Confirm every measured value on your own system and package only after fermentation is complete and gravity is stable.
Pre-Prohibition Porter all-grain recipe: Quick Facts
| Field | Value |
|---|---|
| Style | BJCP 2021, 27A Historical Beer: Pre-Prohibition Porter |
| Strength | 5.5% ABV; OG 1.056; FG 1.014 |
| Colour | 47.3 EBC / 24.0 SRM |
| Bitterness | 25 IBU |
| Batch | 23 L finished beer / 6.08 US gal / 5.06 Imp gal; formulated at 75% brewhouse efficiency |
Historical and Technical Context
Pre-Prohibition Porter describes American porter made before national Prohibition, when British-derived dark ale evolved around domestic malt, adjunct grain and American hops. Records and later descriptions show a family of brown to dark beers that could be fermented with ale or lager yeast. The style was more robust than modern sweet brown ale but generally less burnt than stout.
This formulation combines pale malt with maize, brown malt, caramel malt and a restrained black-malt fraction. Cluster establishes a historically compatible bitterness and an English-type finishing hop links the beer to porter ancestry. A clean ale culture keeps the focus on grain, molasses-like caramel and cocoa while finishing dry enough for repeated drinking.
American brewers adapted porter to local materials and regional markets rather than preserving a single London formula unchanged. Modern home brewers can make that adaptation explicit without borrowing a proprietary historical recipe. The recipe uses available generic ingredients and a fully controlled fermentation for a safe 23 L batch.
Technical Parameters
| Parameter | Target | Acceptable Range | Notes |
|---|---|---|---|
| Colour | 47.3 EBC / 24.0 SRM | 35.5-59.1 EBC / 18-30 SRM | Brown to very dark brown with garnet highlights, but not opaque black. |
| Bitterness | 25 IBU | 20-30 IBU | Medium bitterness balances roast, caramel and maize without stout-like severity. |
| Body | Medium | Medium to medium-full | Rounded dark malt and adjunct grain create fullness while attenuation preserves drinkability. |
| Alcohol Strength | 5.5% ABV | 4.5-6.0% ABV | Calculated from OG 1.056 and FG 1.014 using (OG-FG) x 131.25. |
| Carbonation | 2.3 volumes CO2 | 2.1-2.5 volumes CO2 | Moderate carbonation lifts the dark malt and keeps the finish from becoming syrupy. |
| Original Gravity | 1.056 SG | 1.046-1.060 SG | Measure after a thorough chill and mix; dark wort can hide stratification in the kettle. |
| Final Gravity | 1.014 SG | 1.010-1.016 SG | Package only after this reading is unchanged for at least 72 hours and the flavour is free from fermentation faults. |
| Apparent Attenuation | 75% | 70-80% | The target is calculated directly from the stated original and final gravities. |
| Final pH | 4.30 | 4.15-4.45 | The endpoint should be smooth and clean, without sourness or alkaline roast harshness. |
| Serving Temperature | 10°C / 50°F | 8-12°C / 46-54°F | Cellar-cool service exposes molasses, toast and cocoa better than refrigerator-cold service. |
Sensory Profile
Visual
Deep brown with ruby-garnet edges and a persistent tan head. The beer should remain translucent in a narrow glass; pitch black colour or an oily appearance would imply excessive roast or body.
Aroma
Toasted bread, cocoa, caramel and a low molasses impression are joined by faint maize and earthy-spicy hops. Fermentation is clean to lightly fruity, with no sourness, burnt rubber, butter or strong alcohol.
Taste
Caramel and toasted grain open into cocoa and a restrained coffee edge, balanced by smooth medium bitterness. The finish is moderately dry with a low earthy hop echo, avoiding burnt ash, sharp acidity and sugary heaviness.
Food Pairings
| Category | Suggested Dishes | Pairing Principle |
|---|---|---|
| Barbecue | Smoked beef, pork shoulder, grilled mushrooms | Dark malt echoes char while carbonation and bitterness cut rich sauce. |
| Stew | Beef stew, lentil stew, mushroom ragout | Toast and cocoa deepen browned savoury flavours without stout-level roast. |
| Cheese | Aged cheddar, smoked Gouda, nutty Alpine cheese | Caramel malt matches mature dairy and the dry finish clears salt. |
| Shellfish | Grilled oysters, crab cakes, mussels in broth | Moderate roast contrasts shellfish sweetness while hops refresh. |
| Dessert | Molasses biscuit, cocoa cake, walnut tart | The beer mirrors dark sugar and cocoa but remains drier than the dessert. |
Malts and Fermentables
| Malt or Fermentable | Quantity | Percentage | Function | Notes |
|---|---|---|---|---|
| American pale malt | 3.90 kg / 8.60 lb | 72.9% | Base fermentables | A clean, lightly grainy base for the dark and adjunct fractions. |
| Pre-gelatinised flaked maize | 650 g / 22.93 oz | 12.1% | Adjunct fermentables | Adds a subtle cereal roundness while reducing heaviness. |
| Brown malt | 400 g / 14.11 oz | 7.5% | Toast and cocoa | Provides porter depth without the sharpness of a large black-malt charge. |
| Medium-dark caramel malt | 250 g / 8.82 oz | 4.7% | Caramel and dark sugar | Builds the rounded historical malt centre. |
| Black malt | 150 g / 5.29 oz | 2.8% | Colour and dry roast edge | Keep measured and avoid pulverising it into flour. |
Malt notes: Total grist: 5.35 kg / 11.79 lb; percentages total approximately 100%. The flaked maize is pre-gelatinised and may enter the mash directly. If mash pH falls below 5.2, correct with measured brewing liquor rather than adding alkaline salts by recipe alone.
Hopping Schedule
| Hop | Quantity | Time | Alpha Acids | Function | Contribution |
|---|---|---|---|---|---|
| Cluster | 28 g / 0.99 oz | 60 minutes | 7.0% alpha acids | Firm American bittering | 20 IBU |
| East Kent Goldings | 25 g / 0.88 oz | 15 minutes | 5.0% alpha acids | Earthy-floral porter finish | 5 IBU |
Yeast, Microbiology and Adjuncts
| Component | Quantity | Function | Technical Notes |
|---|---|---|---|
| Primary yeast: clean American ale culture with medium attenuation | Approximately 210 billion viable cells, or one adequately fresh 11 g / 0.39 oz dried culture at the maker’s rate | Clean dark-ale fermentation | Hold temperature steady so roast and adjunct grain remain clearer than esters. |
| Alternative yeast: neutral lager culture | Approximately 450 billion viable cells for a 10°C / 50°F pitch | Historically plausible cool-fermented alternative | Use only with full temperature control, a diacetyl rest and several weeks of lagering. |
| Yeast nutrient and kettle fining | Complete nutrient at the labelled rate plus 2 g / 0.07 oz kettle fining | Fermentation reliability and settling | Add with 10 minutes left; water salts must be derived from measured source water. |
Detailed Procedure
01 Preparation and Milling
Preparation and Milling — Prepare 36 L / 9.51 US gal / 7.92 Imp gal of chlorine-free liquor. Heat 17 L / 4.49 US gal / 3.74 Imp gal for mashing and reserve 19 L / 5.02 US gal / 4.18 Imp gal. Mill pale and character malts moderately fine while retaining husks, then blend in the pre-gelatinised maize. Keep dark-malt dust out of the lauter outlet.
02 Mashing
Mashing — Mash at 66°C / 151°F for 60 minutes, stirring thoroughly at dough-in. Target pH 5.2-5.4 at room-temperature equivalent, confirm conversion, then raise to 76°C / 169°F for a 10-minute mash-out. This balance of fermentability and dextrin supports FG 1.014 without making the beer sweet.
03 Lautering and Sparging
Lautering and Sparging — Recirculate gently until large particles settle, then sparge at 76°C / 169°F to collect 29.5 L / 7.79 US gal / 6.49 Imp gal. Stop at SG 1.010 or pH 5.8; dark husk material becomes astringent when over-rinsed. Use treated top-up liquor if the planned kettle volume is not reached.
04 Boil and Hopping
Boil and Hopping — Boil uncovered for 60 minutes. Add 28 g / 0.99 oz Cluster at 60 minutes and 25 g / 0.88 oz East Kent Goldings at 15 minutes; add nutrient and kettle fining at 10 minutes. Finish near 25.5 L / 6.74 US gal / 5.61 Imp gal at OG 1.056, allowing approximately 2.5 L / 0.66 US gal / 0.55 Imp gal for trub and transfer losses.
05 Cooling and Fermentation
Cooling and Fermentation — Chill to 18°C / 64°F, oxygenate once and pitch the full ale culture. Hold 18-19°C / 64-66°F for four days, then allow 20°C / 68°F to finish. When SG 1.014 is unchanged for at least 72 hours, check for diacetyl and acetaldehyde, then cool to 5°C / 41°F over two days and condition for 10-14 days.
06 Packaging
Packaging — Package only after SG 1.014 has remained unchanged for at least 72 hours. Transfer with minimal oxygen and carbonate to 2.3 volumes CO2. For 23 L / 6.08 US gal / 5.06 Imp gal at roughly 20°C / 68°F, about 125 g / 4.41 oz dextrose is a planning estimate; recalculate for actual volume and temperature. Use sound pressure-rated bottles or a purged keg and never add unfermented wort unless its fermentability and required pressure have been calculated.
Variations
- Ferment with a neutral lager culture at 10°C / 50°F, complete a 15°C / 59°F rest and lager four weeks for the cool-fermented historical branch.
- Replace the flaked maize with the same mass of pre-gelatinised rice for a cleaner adjunct profile and slightly leaner finish.
- Replace 50 g / 1.76 oz black malt with pale malt for softer roast and a colour nearer the lower style boundary.
- Shift 10 g / 0.35 oz of the Goldings charge to 5 minutes for more hop aroma, recalculating Cluster to retain 25 IBU.
- For a molasses nuance, replace 150 g / 5.29 oz pale malt with 100 g / 3.53 oz dark brewing sugar, adding it during the final 10 minutes and rechecking OG.
Pre-Prohibition Porter all-grain recipe: Frequently Asked Questions
Why does the porter taste burnt?
Check the colour and type of black malt, the crush and the sparge endpoint. A small measured black fraction should add dry depth, not ash. Replace part with brown malt next time and stop runoff at the stated pH and gravity rather than trying to smooth burnt flavour with sweetness.
Can lager yeast really be used?
Yes, the historical style permits ale or lager fermentation, but the processes are not interchangeable. A lager culture needs roughly twice the cells, a cold pitch, a controlled warm finishing rest and longer conditioning. Do not pitch one small sachet into warm wort and call the result lagered.
What causes a thin, sharp finish?
An unexpectedly low OG or FG, excessive sulphate, high carbonation or too little brown and caramel malt can expose roast and bitterness. Verify measurements first. Restore balance in the next batch through correct grist and water rather than adding unfermented sweetener to packaged beer.
How long should the porter mature?
The ale version is usually integrated after two weeks of cool conditioning, while a lager-fermented version benefits from four or more weeks cold. Release by sensory condition: green apple, butter, yeast bite or harsh roast indicate more time or a process fault, not a need for oxidation-prone transfers.
Sources
- BJCP 2021 official category page — Historical Beer and Pre-Prohibition Porter
- BJCP 2021 official consolidated Beer Style Guidelines
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