Friday, June 12, 2009

The Parti-Gyle Experiment

There are plenty of way to make homebrewing more productive, more cost effective, and more enjoyable. OK, so we'll have to see about the third part of that statement, but it looks like I've stumbled upon a method to bring the first two to fruition. I guess we'll start with a story.

I'd been talking with Nate about a couple brews I'm planning to make, one being a funky, saison-esque table beer while the other was a big American Barley Wine. Nate suggested that I make the table beer from the second runnings of the barley wine. This got me thinking, and after a quick Google search, I found a reprint of Randy Mosher's Parti-Gyle Brewing article on Brewing Techniques.

Parti-gyle brewing is an ancient technique that uses one mash to make multiple beers. The classic example is of course the "Belgian Hierarchy" of Tripel, Dubbel, and Single, each made with a subsequent mashing of one grain bed. This allows for a greater variety in styles while cutting the length of a brew day, in contrast to brewing multiple beers from several mashes. Needless to say, the shortened brew day can have significant advantages, from reducing brewer's exhaustion to not getting harassed by one's significant other that you "wasted" your whole day on your "dumb hobby" (DISCLAIMER: Mrs. Muckney Brewing does not consider brewing a "dumb hobby", or so she says).

The process is simple enough, but does have its own drawbacks, though minimal, IMHO. It does, however, throw a new calculation into the mix, and can confuse brewing software. Here we go.

First, one must decide on the gravity of each brew. For this example, we'll go with, say a Barley Wine and a table beer. Coincidence, I think not! Let's say we're shooting for a 5 gallon batch of Barley Wine with a starting gravity of 24.22P and 3 gallons of table beer at 7.3P. To figure out the target gravity of the "mother ale" as I call it, use the following formula.

(D1 x V1) + (D2 x V2)/Vtotal*

where D is the density of the target beers 1 and 2 in Plato and V is the desired volume of the beers in gallons. Vtotal is the total volume of the target beers.

Simple enough, right? Now running our numbers through the formula gives us the following:

(24.22 x 5) + (7.3 x 3)/8 = 17.875

For those following at home, that translates to 1.074 SG.

Step two is to develop the recipe for the Mother Ale. Using whatever grain bill you'd like, shoot for a target SG of 1.074. The brewing software of your choice is a big help in figuring this out. It keeps the calculator out of it. Once you have the grain bill, the next step is to figure out the pre-boil volumes needed. This will vary from system to system, and with the length of boil used.

Step three is to complete the recipe for each beer. For my current experiment, I found it useful to create each beer separately in Beersmith, manipulating the grain bill to get your target gravity, then working through the recipe as normal to get the correct hop dosage and such.

Brew Day

Implementing the process has its own hurdles. First, having two brews going at the same time may be a bit of a struggle. Equipment limitations may render this technique moot, as it applies to a time saving technique. My plans for the upcoming brew day is to boil the 6 gallons (calculated pre-boil volume) of Barley Wine in Nate's converted keg on the back deck for 90 minutes, while brewing the 3.5 gallons (again, pre-boil volume) of table beer inside on my stove in my brewpot for 60 minutes.

Yes, I do think I'm crazy to attempt to run two boils simultaneously, but with a bit of planning, and some luck, I'm hoping to pull it off. Keep an eye out for updates.

Sounds fun, huh? I think so. There are some concerns noted in Mosher's article, the most pressing, in my opinion, is the color of the second beer. The runnings may be a bit light, so Mosher suggests a mini-mash on the side to get to the desired color. Depending on the style, a longer boil of the second runnings could also help achieve a darker color, but may affect the final volume of the beer, let alone the flavor. That sounds like another experiment for another post.

The only issue I'm currently having is choosing a sparge method. I'm leaning towards a batch sparge, which seems to be more traditional, but a continuous sparge may allow for more precise wort collection. I'm still doing research on this. Any ideas would be appreciated.

Stay tuned for updates.


*Calculations from Parti-Gyle Brewing by Randy Mosher, republished from BrewingTechniques' March/April 1994. For more information, including calculation tables, please read the article.


Adam said...

I'll be in Indiana (PA that is) this weekend for my wifes X country coaches retirement party. Not sure I'll have any time outside of those activities. Might be cool to look you Indiana folk up :-)

Dave said...


Like today the 13th or next weekend the 20th? If you need any beer tips, let me know. I'm at a golf outing today, but will have my Crackberry.