For steeped grains plus malt extract:
2021 BJCP British brown ale: "Characteristic Ingredients: British mild ale or pale ale malt base with caramel malts. May also have small amounts darker malts (e.g., chocolate) to provide color and the nutty character. English hop varieties are most authentic."
Vital Statistics: OG: 1.040 – 1.052; IBUs: 20 – 30, FG: 1.008 – 1.013, SRM: 12 – 22, ABV: 4.2 – 5.9%
A distinction was made between northern and southern English brown in older style guidelines. The northern version was stronger (4.4 to 5.2% compared to 2.7 to 3.2%) and more bitter.
The most common malts from Brew-Analytics are chocolate (median: 2.7%), British base malts like Maris Otter (median = 77%) or pale ale malt (75%), medium crystal 60L (7.2%), biscuit malt (5%), or dark crystal malts (120L, 4%). Adjuncts like torrified wheat and maize are possibilities.
Zainasheff recommends using no more than 10% crystal malts for a northern English brown ale. Biscuit or Victory malt can be used with American malts to simulate British pale ale malts or to bump up nutty flavors. Sugars, such as dark invert sugars, and adjunct grains are possibilities, but Zainasheff recommends against these.
Daniels' analysis suggested 10 to 15% crystal malt and 2 to 3% chocolate malt (Table 20.9 and p. 228).
The typical hops are British strains like Golding varieties, Fuggle, Target, and Challenger. US hop possibilties might be Willamette or Cascade. Many recipes are 100% bittering. Small late hop additions are possible. Daniels reports that late boil additions (last 10 minutes) are "fairly common" and about .5 oz for 5 gallon batches (.74 g/l). Aim for a BU/GU ratio of .49. Dry hopping is possible but uncommon.
British ale yeasts that attenuate well are recommended. The most common yeasts are Fermentis S-04, Fermentis US-05, Nottingham, Windsor, and White Labs English ale (WLP 0002).
Beer-analytics.com British brown ale analysis
Daniels, R. (2001). Designing great beers: The ultimate guide to classic beer styles. Brewer's Publications.
Foster, T. (2007, September). Brown ale. Brew Your Own, 26 - 31
Strong, G. (2024, May-June). British brown ale: An old sytle with a much more recent history. Brew Your Own, p. 18 - 20.
Zainasheff, J. (2010, March-April). British balance: Northern English brown ale. Brew Your Own, 21 - 25