Parti-Gyle Brewing: How to Get Two Beers From One Mash

Last fall I brewed a barleywine and a mild on the same day using the same grain bill. One massive, boozy sipper and one easy-drinking session ale, both from a single mash. Total grain cost was maybe 15% more than brewing just the barleywine alone. That's parti-gyle brewing, and once you try it, you'll wonder why you ever let those second runnings go down the drain.

Parti-gyle (rhymes with "style") is one of the oldest brewing techniques around. Before the invention of the hydrometer, English brewers routinely collected multiple runnings from their mash tun. The first runnings made strong ale. The second became ordinary bitter. A third might produce small beer for children and servants. It was just how brewing worked for centuries.

How It Actually Works

The concept is dead simple. When you mash grain for an all-grain brew, the first wort that drains from the mash tun is sugar-rich and high gravity. As you continue to sparge (rinse the grain bed), each successive gallon of runnings contains less sugar. In normal brewing, you combine all the runnings into one kettle. In parti-gyle, you collect them into separate kettles.

There are two main approaches:

The first-runnings-only method

Drain the mash tun completely without sparging. This concentrated first wort becomes your big beer. Then add hot water back to the grain bed, let it rest 15 minutes, and drain again for your small beer. This is the simplest approach and gives you the cleanest separation between the two beers.

The split-runnings method

Begin your sparge normally but collect the runnings into two separate vessels. Divert the first portion (typically the first 3-4 gallons) into one kettle, then switch to a second kettle for the remaining runnings. This gives you more control over the gravity of each beer but requires knowing when to make the switch.

Planning Your Gravity Split

Here's where a little math helps. Say your recipe calls for 15 pounds of grain to make 6 gallons of 1.072 wort for a normal-strength IPA. In a parti-gyle scenario, that same grain can produce:

• First beer: 3 gallons at approximately 1.090-1.100 (double IPA territory)
• Second beer: 3 gallons at approximately 1.040-1.048 (session ale or mild)

The total gravity points are roughly the same, you're just distributing them differently. Think of it like pouring from a pitcher: the first glass is strong, the last glass is weaker, but the pitcher held the same total amount of sugar.

Classic Parti-Gyle Pairings

The beauty is that you can take the same base grain bill in two wildly different directions during the boil by varying your hop schedule, yeast, and additions:

• Barleywine + English Mild: The most traditional pairing. Rich, complex strong ale from the first runnings; a low-gravity, malt-forward session beer from the second
• Imperial Stout + Dry Stout: Add roast barley and chocolate malt to both kettles. First runnings become a massive imperial; second runnings make a perfectly drinkable Irish-style dry stout
• Double IPA + Pale Ale: Same grain base, same hops, different intensities. The pale ale from second runnings makes a great daily drinker
• Belgian Tripel + Belgian Single: First runnings with Belgian candi sugar for the tripel; second runnings fermented clean for a monastic table beer

Brew Day Logistics

The biggest challenge with parti-gyle is having enough equipment. You need two boil kettles (or one kettle and a holding vessel), two fermenters, and enough propane or burner capacity to run two boils. Here's how I handle it:

1. Mash as normal with your full grain bill. Use your standard mash temperature and duration
2. Collect first runnings into your primary boil kettle. Let the mash tun drain completely, don't sparge yet
3. Add sparge water to the grain bed at 170F. Stir gently, let it rest 15 minutes
4. Collect second runnings into a second vessel. A large stockpot or a sanitized bucket works
5. Start boiling the first beer immediately. While it boils, prepare your second kettle
6. Boil the second beer once the first is done, or simultaneously if you have two burners
7. Cool and pitch separately with appropriate yeast for each beer

Total brew day is about 5-6 hours instead of the usual 4, but you end up with two completely different beers. That's incredible efficiency for one day of work.