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The Automagical Parti-Gyle Recipe Worksheet


I worked this spreadsheet up out of frustration: ProMash is great, but not very useful when you're brewing parti-gyle. For those who don't know, parti-gyle brewing is the ancient way of making two (or even three) beers from a single mash -- as practiced in Belgium and Great Britain. The first beer is strong and robust, while the second is milder. The advantage is in time savings: although your brew day is somewhat longer, you get two beers for less time invested. One trip to the brew store, one cleanup cycle, one brew day instead of two. The equipment involved is somewhat simpler, and you get the pleasure of brewing beer like the Trappist monks of old.

I can't explain everything involved in parti-gyle brewing and batch sparging here, but you can get lots of information on the theory and practice in the references listed at the bottom of this page.

The spreadsheet is prefilled with a recipe where the first beer is an American IPA and the second is a Robust Porter.

Get the Automagical Parti-Gyle Worksheet:
  • Zipped Excel
  • Uncompressed Excel

    I brew the two beers serially: I mash in, then run off the first beer and boil it. Once the boil finishes, I chill the beer and run it to the fermenter. While the chiller is running on the first beer, I am heating sparge water for the second beer. Once the first beer is in the carboy, I batch-sparge the second right onto the first beer's spent hops, and boil it (usually with a second hop addition).

    In the spreadsheet, all the areas you need to fill in are highlighted in orange. The non-highlighted areas are calculated values, so don't modify these unless you want to adjust my formulas.

    The spreadsheet makes it easier to figure the gravity of the first and second beer, given the two runoffs. It assumes that the two beers are of equal size (half the "Entire Batch Volume"), so the first beer gets 60% of the extract, the second gets 40%. (This parameter is adjustable by the "% extract in first beer" field under "Constants".)

    To work up a recipe, enter your grain bill at the top. You need to enter the weight in pounds, the theoretical extract in pts/lb/gal, and the color in Lovibond. Then fill in the "Entire Batch Size" field -- this is the total amount of beer you want to brew (say, two 5.25-gallon batches). The system figures out the gravity and color of the entire wort, which will be about halfway between the gravities of the two beers.

    Now enter your volume of strike water and desired mash temperature. The sheet calculates the required strike temp to hit your mash temp, plus the mash-to-water ratio (in qts/lb). Given the total batch size and the amount of mash water, the system figures the amount of sparge water you need for each brew. The second brew always requires more sparge water than the first. I use a batch-sparge system: add all the sparge water in one go, stir it up, let it settle a few minutes, recirculate until clear, and then run off as quickly as possible. You can use a more typical fly sparge if you wish.

    The kettle volume and gravity is shown, with spaces to enter sugars or extracts added post-mash. Just fill in the weight, maximum extract, and color for these as you did for the mashed grains at the top. Cane sugar and dry malt extract are normally 46 pts/lb/gal. If you add sugars, it will add their gravity and color contributions to the totals.

    For the second beer, there are two sugar rows and two "Capper" rows. A "capper" is an amount of grain stirred into the tun as you add the second batch of sparge water -- usually crystal, black, or other grain that doesn't require mashing. This lets you tune the second beer's flavor profile. In the spreadsheet, I'm brewing a porter as the second beer, so I use some dark grains as the capper, plus some dry extract to bump up the gravity.

    Since I boil the second beer on top of the first beer's (nearly) spent hops, calculating the IBUs is a little complicated. The first beer's flavor and aroma hops still have some bitterness to give after their short boil, and this is tricky to estimate. The spreadsheet does the calculation for you, figuring in the IBUs lost from the first beer's 5- and 15-minute hops. It also figures out the bitterness-to-gravity (BU:GU) ratio, which is a good way to find the correct balance of hops and malt. IBUs are figured using the system from the Ray Daniels book Designing Great Beers.

    If you use other hop addition times, you can modify the spreadsheet to your needs. (You'll need to look up the % utilization for different boil times.) Or, you might want to brew your beers in parallel (boil them both at the same time) in order to get things done quicker. My equipment won't allow for this, but if you want to do that, then adjust the hop calculation area accordingly.

    After each boil finishes, measure the final volume and gravity, and enter into the appropriate "Actual vol" and "Actual OG" fields. You'll then see the efficiency of your mash at the bottom of the spreadsheet. This is aggregate system efficiency, so any lost wort in the mash tun is included in the figure.

    If you find this sheet useful, or have suggestions on how to improve it, I'd love to hear from you. Just email me: cat at pobox dot com.

    --Chris Tweney
    February 2005

    References

    Web Sites:

  • Randy Mosher's Parti-Gyle Article
  • Drew Avis's SWIG Method
  • Calculating Strike Water Temperature
  • Cheap 'n Easy Batch Sparge Brewing
  • Bay Area Mashers Batch Sparging Guide

    Books:

  • Radical Brewing by Randy Mosher (2004)
  • Designing Great Beers by Ray Daniels (1996)
  • Belgian Ale by Pierre Rajotte (1992)
  • The Theory and Practice of Brewing by Michael Combrune (1762)