Start with the beer in your head

Porter is a broad church. Before you weigh out a single grain, decide what kind of porter you actually want to drink. A brown porter is softer and nuttier, sitting around 4.2–4.8% ABV with restrained roast. A robust porter pushes up to 5.5–6% with more chocolate and coffee character and a firmer hop bite. Both are valid; they just need different grists.

For a reliable, balanced example, aim for an original gravity of 1.048–1.056, an ABV of 4.5–5.5%, bitterness of 30–40 IBU and a colour somewhere between 60 and 90 EBC. The roast should be clearly present but never ashy, and the bitterness should support the malt rather than fight it. Write those numbers down. Everything else is a decision in service of them.

Build the malt bill from the base up

Start with 75–85% of a good pale ale malt. Maris Otter brings a biscuit backbone that suits porter beautifully, though any quality pale malt will do the job. Then layer your speciality malts in small, deliberate additions rather than throwing everything in the sack.

• Brown malt, 5–8% — the historical heart of porter. Dry, toasty and faintly smoky, it adds complexity without harshness.
• Chocolate malt, 4–6% — cocoa and dark coffee. This is your main roast note.
• Black malt, 2–3% — sharp and ashy in quantity. Use it sparingly for a crisp roast edge, or leave it out entirely.
• Crystal malt, 5–8% — something in the 60–120 EBC range adds caramel, colour and body, and helps round off the roast.
• Munich or Vienna, 5–10% — optional, but a useful way to add depth without more roast.

Keep your total dark and roasted malts under about 15% of the grist. Go beyond that and you will get a thin, acrid beer that tastes like burnt toast rather than a proper porter.

Keep the hops English and restrained

Porter is a malt-forward beer, so hops are there to balance, not to star.

Choose a clean English variety for bittering — Fuggle, Goldings, Challenger or Target all work well. Calculate your bitterness to hit a bitterness-to-gravity ratio of roughly 0.6 to 0.7. For an OG of 1.052, that means around 34 IBU. A single late addition of 20–30g at ten or fifteen minutes gives you a gentle earthy, spicy aroma without obscuring the malt.

Dry hopping is optional and traditional porters rarely featured it. If you do, keep it to 20–30g for three or four days. Heavy citrus-forward hopping will clash badly with roast character.

Choose yeast and fermentation for body

An English ale strain with moderate attenuation and good flocculation is the right tool here. You want something that finishes around 70–75% apparent attenuation, leaving a final gravity of 1.012–1.016. A beer that dries out to 1.008 will taste thin no matter how good your grist was.

Pitch a healthy, well-oxygenated starter and ferment at 18–20°C for the first three or four days, then let the temperature rise freely to 21–22°C to encourage full attenuation and clean up any diacetyl. Keep it cool early to avoid excessive fruity esters, which can muddy the roast. Carbonate gently — 1.8 to 2.2 volumes of CO2 is about right, giving a cask-like condition rather than a fizzy pint.

Water, mash and the details that matter

Dark malts acidify the mash, and this is where many home-brewed porters go wrong. If your water is very soft, your mash pH can drop below 5.2, producing a sharp, sour roast character. Aim for a mash pH of 5.4–5.5, adjusting with a little bicarbonate if needed. If your water is hard and alkaline, you may need acid instead.

Mash at 66–67°C for a full-bodied result, and sparge with water no hotter than 75°C. Over-sparging or sparging too hot will extract harsh tannins from the roasted grains and leave you with an astringent finish that no amount of conditioning will fix. A straightforward 60-minute boil is plenty.

Taste, adjust and brew it again

Take notes every time. If the beer tastes ashy or harsh, cut back on black malt or check your mash pH and sparge temperature. If it feels thin, raise the mash temperature, add a little more crystal, or look at your yeast attenuation. If it comes across as flabby or sweet, increase your bittering charge or reduce the crystal.

Change one variable at a time so you know what caused the difference. Brew the same recipe again within a month, taste the two side by side, and you will learn more in two batches than in ten random ones. That is how a good porter becomes your porter.