Two Beers from One Mash

I got into homebrewing for probably the most senseless of reasons. I was already a craft beer drinker, so I thought maybe I could save a few bucks cutting out the middleman and making it myself. I made the investment right off the bat and started all-grain brewing with my first batch. While I only ended up with three gallons instead of five, I was hooked. I then spent my time trying to make my beer bigger while keeping costs down.

There are two awesome ways to turn a five gallon all-grain beer into a ten gallon batch of the good stuff.

The first is a technique long since abandoned by those who originated it, called parti-gyle. In this method you are creating two beers. You will brew a strong beer (1.080 or greater gravity) while following a normal brew day (with a slight deviation at mash-out). After your strong beer is into fermentation, you will then mash in again with the same grain. You will then proceed again with a normal brew day. You can net about 40-50% of the original gravity of your first beer using this method, so long as you follow some specific mashing out steps. Add as much strike water as you can so you can avoid having to sparge. When your first mash is ready to lauter, you will drain the mash tun dry without adding any sparge water. If you find yourself coming up short in the kettle, you can add a gallon or two of water that is no hotter than 155 F, as any hotter and you can kill the enzymatic activity you’re going to need for batch two. Use as little sparge water as you can. The more you add for this first beer, the weaker beer number 2 is going to be.

The second mash can be a little trickier if you forget some basic all grain principles. First off, your strike water temperature is going to need to be adjusted from what it was in mash number 1. Your mash should still be hot, so plan on adding cooler water than you did before to hit your desired mash temperature. Also, you are still going to need to stir the mash and have it form a filtering bed at lautering.

When forming a recipe, it is very important to keep the second beer in mind. Be sure not to overdo the crystal malts. Also, if making a dark beer, keep highly acidic malts like Black Patent to low levels. You are going to get more color and flavor from your specialty malts proportionate to fermentable sugar than you will from your first beer. In the recipes at the bottom of this blog post is a recipe for an American Strong Ale/Petite IPA that is darn tasty. Or at least, it can serve as inspiration for your own parti-gyle beer.


The other way to super-size your 5 gallon batch is to utilize malt extract, and then split the batch so you can get two distinct beers. Your brew day will be the exact same all the way up until knockout, or when you kill the flame on the kettle and would normally start chilling. Depending on what you’re making, you’ll add about 1.25 pounds of malt extract for every percent of alcohol you want. So if you’re making 5 gallons of a 6 percent beer, you would need about 7 pounds of malt extract. As for procedure, you’re basically doing a large “partial mash” beer. But since we’re making 10 gallons, all of our hop additions will need to be doubled. This is something commonly overlooked with this method. Remember to double all the hop additions! When you add the malt extract at knockout, you will then chill it down as usual. But you will need to add water to bring the volume up to 10 gallons and also bring the future beer to its proper strength. I like to do this step in the fermenter so I know I’m getting it right. I’ll have both fermenters side by side while I empty the kettle equally into both. I will then use gallons of spring water to top them both up to five gallons. Now comes my favorite part. I rarely make 10 gallons of the same beer. There are quite a few beers with similar recipes that only differ when it comes to the yeast, and even more that are just tasty with a non-traditional yeast choice. You can make your favorite IPA, but for 5 gallons of it pitch an Abbey or even Saison yeast. Take a porter recipe and use an American strain on one, and a super malty and fruity English strain on the other. The possibilities are only as confining as your imagination. At the bottom of this post I’ve provided my super tasty Stout/Belgian Stout recipe. You would never know these beers came from the same kettle!


American Strong Ale (“Arrogant” Beer)   —   La Petite IPA   (Parti-Gyle Method)

18 lb Briess Pale Malt

1 lb Aromatic Malt

½ lb Special B Malt

½ lb Crystal 60 L Malt

¼ lb Victory Malt


Strong Ale Hop Schedule:

1 oz Magnum 60 min

2 oz Cluster 10 min

3 oz Ahtanum 2 min

Wyeast 1028 or White Labs 013

La Petite IPA Hop Schedule:


1 oz Cascade 60 min

1 oz Nugget 10 min

1 oz Simcoe 3 min

1 oz Mosaic 0 min

Wyeast 1968 or White Labs 002 (This yeast choice is very important as it will leave some body in the beer)

American Stout/Belgian Stout (10 Gallon Split Batch with Malt Extract)


10 lb Briess 2-row

1 lb Pale Chocolate

1 lb Amber Malt

¾ lb Special B Malt

¾ lb Roasted Barley

¾ lb English Chocolate Malt

¼ lb Crystal 40 Malt

6 lb Dry Malt Extract (6.6 lb if liquid)

Hop Schedule: (These have already been adjusted for the batch size. DO NOT DOUBLE!)

1 oz Magnum 60 min

2 oz Willamette 10 min

1 oz Styrian Goldings 5 min

1 oz Cascade 2 min

5 gallons-Wyeast 1332 or White Labs WLP041

5 gallons-Wyeast 3787 or White Labs WLP530 (Wyeast 1214 or White Labs 500 is also a great choice)

Beer Blog, Brewing Techniques & Recipes