Brewing Imperial stout at home

Name: Brewing Imperial stout at home
Yield: 20 L
Ingredients: 6.75 kg Pale ale malt; 0.59 kg Flaked oats; 0.52 kg Chocolate malt; 0.52 kg Roasted barley; 0.49 kg Caramunich II; 48 g Magnum; 26 g East Kent Goldings; SafAle US-05: 10–16 g (0.35–0.56 oz) for 20 L (about 5.3 gal) (50–80 g/hl) – with this high original gravity, pitch about twice as much.

Very strong and full-bodied with roast, chocolate and coffee.

Base recipe for 20 litres (5.3 gal), calculated with the Brauwerkstatt beer creator. With one click you can adapt it to your batch size, bitterness, colour or alcohol content.

Adapt in the beer creator

Typical figures

Alcohol	8.0–11.0 %
Bitterness	50–90 IBU
Colour	80–150 EBC (41–76 SRM)
Carbonation	4.2 g/l (2.1 vol)
Yeast	SafAle US-05 (top-fermenting)
Fermentation temperature	18–20 °C (64–68 °F)
Brewing water	harder, for dark beers

Recipe for 20 litres (5.3 gal)

Original gravity: 20.3 °P (SG 1.084)
9.5 % vol
65 IBU
110 EBC (55.8 SRM)
Final gravity: 4.3 °P (SG 1.017)

Grain bill

Pale ale malt	6.75 kg (14.88 lb)	76 %
Flaked oats	592 g (20.9 oz)	7 %
Chocolate malt	520 g (18.3 oz)	6 %
Roasted barley	520 g (18.3 oz)	6 %
Caramunich II	491 g (17.3 oz)	6 %

Hops

Magnum 13.0 % α	48 g (1.69 oz)	60 min
East Kent Goldings 5.5 % α	26 g (0.92 oz)	15 min

Yeast

SafAle US-05: 10–16 g (0.35–0.56 oz) for 20 L (about 5.3 gal) (50–80 g/hl) – with this high original gravity, pitch about twice as much.

Mash schedule

68 °C (154 °F) · 60 min

Brewing water

Mash water	31.0 L (8.19 gal)
Sparge water	3.5 L (0.92 gal)
Total water	34.5 L (9.11 gal)

Brewing steps

Clean and sanitise everything that touches the wort after the boil.
Measure out 34.5 L (about 9.1 gal) of water and treat it with the brewing-water calculator. Dark beers cope well with harder water; aim for a mash pH of 5.3–5.5.
Split the water: mash water 31 L (about 8.2 gal), sparge water 3.5 L (about 118 fl oz).
Heat the mash water to 71 °C (160 °F) and mash in 6.75 kg (14.9 lb) Pale ale malt, 0.59 kg (1.3 lb) Flaked oats, 0.52 kg (1.1 lb) Chocolate malt, 0.52 kg (1.1 lb) Roasted barley and 0.49 kg (1.1 lb) Caramunich II (gives about 68 °C / 154 °F).
Rest: 68 °C (154 °F), 60 min. Iodine test at the end: no blue colour = starch converted.
Measure mash pH 10–15 min after mashing in (cool the sample to 20 °C / 68 °F). Target 5.4–5.5.
Mash out: heat to 78 °C (172 °F) and hold for 10 min.
Rest 10–20 min, lauter slowly and sparge with 3.5 L (about 118 fl oz) water at 78 °C (172 °F).
Boil the wort for 90 min.
60 min before the end of the boil add 48 g (1.7 oz) Magnum.
15 min before the end of the boil add 26 g (0.92 oz) East Kent Goldings.
10 min before the end of the boil add Irish moss (about 2 g / 0.07 oz, soaked beforehand).
After the boil stir a whirlpool and let it rest for 15 min.
Chill to 18 °C (64 °F), measure original gravity (target 20.3 °P), run 20 L (about 5.3 gal) into the fermenter, aerate well and pitch the SafAle US-05 (amount see yeast).
Primary fermentation 7–10 days at 18–20 °C (64–68 °F).
Measure final gravity (target about 4.3 °P). Priming sugar per bottle from the carbonation calculator (target 4.2 g/l), then bottle.
Bottle-condition for 2 weeks at room temperature, then keep cool. Strong beers improve with 1–3 months of ageing.

Notes

Created with the beer creator (brewhouse efficiency 70 %, final gravity about 4.3 °P).