Gowanus Brewery

Full-mash Brewing

You can see it in every aspect of how we brew beer here, including the full-mash method described below, that we are still learning the basics. For perspective, you could skim through John Palmer’s “How to Brew” or Wikipedia’s article on Mashing and you would see that the sky’s the limit on how complex this stage of brewing can be. Not here. We want to know just enough to carry out a consistent and effective mash, so we can brew beers from start to finish that are truly our own.

This page is the product of our stumbling through how-to’s and homebrew articles and will, without a doubt, evolve over time.


  1. Eight-gallon Kettle (MegaPot with spigot, brewmometer, and bazooka tube)
  2. Four-gallon kettle
  3. Pitcher with quart marks
  4. Thermometer
  5. Wooden spoon
  6. Two range burners
  7. Bucket (with grommeted lid and spigot)

Method (Full-mash, batch sparge):

  1. Get Water: Fill the eight-gallon kettle with hot water from the tap to an initial volume in gallons equal to the weight of grain in pounds divided by four, heat over range to 110 degrees. Fill the four-gallon kettle to the top, ideally to a volume in gallons equal to the weight of grain in pounds divided by two, and bring to 150 degrees.
  2. Add Grain: Add grain to the eight-gallon kettle and stir. Afterwards and up until lautering, stir once every five minutes.
  3. Dough-in: If necessary, heat water to 105 degrees, the “dough in” temperature, and hold at this temperature for 15 minutes. The purpose of this rest is to distribute enzymes and to provide time for water to penetrate the grains.
  4. Protease Rest: After 15 minutes, heat the wort to the next rest at 125 degrees and hold for another 15 minutes. With the MegaPot, this takes between four and six minutes with the burner on high. The purpose of this rest is to promote protease activity, which will improves overall clarity by breaking down naturally occurring proteins found in grain.
  5. Sugar Rest: After the second rest, pour the water from the smaller to the larger kettle and heat the wort, if necessary, to 150 to 155 degrees and hold for 60 minutes. While waiting, refill the four-gallon kettle with the same volume of water as before, ideally equal to the weight of grain in pounds divided by two, which will be used to lauter, but this time heat to 180 degrees. The purpose of this rest is to convert grain starches to sugar. The mash-in temperature, depending on the recipe, may vary between 145 and 160 degrees, with the lower range producing less body and higher alcohol and the higher range producing more body and less alcohol.
  6. Mash Out: Prior to lautering, heat the wort to 170 degrees for 10 minutes for the mash out to preserve the sugar profile.
  7. Lauter: To lauter, put a plastic lid on the wort in the center of the pot and drain a full quart of wort to pour over the lid. The purpose of recirculating the wort is to establish a grain bed that will act like a filter. The plastic lid is just a simple way to add wort back to the kettle without disturbing the grain bed. Repeat two or three times, until the wort pours clearer, then drain off completely to a bucket and remove the plastic lid.
  8. Lauter: Pour the water from the second kettle over the grain bed in the eight-gallon kettle and stir it up. Let the grain settle and replace the plastic lid. Then, just like before, drain a full quart of wort off to pour over the lid and repeat until wort clarifies. Finally, drain the wort off completely to the bucket, which should now be at a total volume of 5.5 gallons.
  9. Full-wort Boil: Empty and clean the eight-gallon kettle, then fill with the sweet wort. Boil for 60 minutes and add hops according to the recipe.
  10. Cool: Allow wort to cool uncovered to 180 to 190 degrees, move to primary fermenter. If primary is glass, it must be preheated with hot water to avoid cracking. Seal with empty water lock covered with foil, or something similar. Let cool to room temperature over night.
  11. Pitch Yeast: Prepare and pitch yeast, as soon as possible once wort reaches room temperature. Fill water lock with water.

There are two areas ripe for fixing up. The first is cooling the wort to room temperature. We need to upgrade to either an immersion or plate chiller, because it takes way too long to cool 5.5 to 6 gallons of wort in an ice bath. The first time around, it took about 90 minutes. For the time being, we are opting to let the wort cool over night in the primary fermenter prior to pitching the yeast. The second issue is minimizing hot-side aeration, which, in practical terms, means minimizing splashing. There are compounds present from the beginning of the mash that react with oxygen to create bad-tasting byproducts. The more oxygen that’s present in the wort, the more byproducts are created.

5 Comments so far
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[…] Christmas Kettle January 11, 2008, 12:00 am Filed under: beer, brewing, equipment This is a preview of things to come! […]

Pingback by Christmas Kettle « Gowanus Brewery

[…] to bring the mash from the protease rest at around 125 degrees to the saccharization rest at 153 degrees, I added […]

Pingback by American Wheat Beer - Started « Gowanus Brewery

I’m also a homebrewer in brooklyn. I’m looking to move up to all grain and full wort boils but heard it is hard to achieve a rolling boil on a stovetop. have you had any problems?

Comment by Jason

Our range, fortunately, has one extra-large burner, so we haven’t had trouble bringing our wort to a rolling boil. I would say, though we haven’t actually experimented, that it would be a challenge to do that on one of our standard-size burners.

Comment by Jeremy

[…] first most important change is to not screw up the mash. Last time, when bringing the mash from the dough in up to the sugar rest, I added water that was […]

Pingback by Gowanus Raspberry Wheat Ale - Recipe Rewrite « Gowanus Brewery

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