What is parti-gyle brewing?

Parti-gyle is a traditional British brewing method where two (or more) beers of different strengths are produced from the same mash. The first runnings produce a strong beer and the second runnings a lighter session beer. Historically, this is how porters and milds were brewed from the same grain bill.

How much extract is in the first runnings?

The first runnings typically contain 57–70% of the total extract, despite being a smaller volume. This is because the initial wort is more sugar-dense. The exact split depends on mash thickness, grain bed depth and sparging technique.

Can I add hops differently to each beer?

Yes, this is one of the great advantages of parti-gyle. You can create an IPA from the first runnings and a mild bitter from the second. Each wort can be boiled separately with different hop schedules, yeast strains and fermentation profiles.

What styles work well for parti-gyle?

Traditional pairings include: strong bitter/ordinary bitter, barley wine/pale ale, Scottish heavy/Scottish light, and imperial stout/dry stout. The key is choosing a grain bill that works at both gravities.

BrewCalcs

Parti-Gyle Calculator

Calculate gravity and volume for two beers from a single mash using parti-gyle brewing.

Total Grain Weight

Total weight of grain in your recipe

Mash Efficiency

Your system mash efficiency percentage

First Runnings Volume

Volume of first runnings to collect

Total Volume

Total pre-boil volume (first + second)

How We Calculate This

Parti-Gyle Method

Total Gravity Points = Grain (kg) x Extract Potential x Efficiency

The first runnings are collected separately from the second runnings. First runnings contain a proportionally higher concentration of extract (sugars).

First Runnings OG = (Total GP x First Extract Ratio) / First Volume

Second Runnings OG = (Total GP x Remaining Extract) / Second Volume

ABV estimates assume 75% apparent attenuation as a rough guide.

Frequently Asked Questions

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Last updated: 2026-03-03

All calculations are estimates. Always verify values and adjust based on your equipment and ingredients.