Brewing Fire-Pit Gruit

While the basic steps that go into brewing haven't changed much over the 6,000+ year history of the beverage, the ingredients and equipment certainly have. As a result, the beverage we call beer today doesn't share much in common with what was being brewed and drank 1,000 years ago. The most significant change to the ingredients over that time has been the dominance of hops over all other brewing herbs. Hops are the perfect spice for beer, they add bitterness, aromatics, boost head retention, inhibit Lactobacillus, and grow like weeds in northern climes (the same places where barley thrives and grapes do not). Even so, it is nice to try the alternatives sometimes to see what the other options are (even if just to affirm your choice).

Over Labor Day weekend I drove from DC out close to the border between Virginia and West Virginia to brew with one of the homebrewers who attended Brewing Locally. When Marty mentioned that he and his friend Martin brew gruit over an open fire, it sounded like an event that I couldn't pass up witnessing for myself. The combination of an arcane beer style, and an crazy brewing technique was something that seemed right up my alley.

Traditionally blends of herbs called gruit were used to balance the sweetness of the malt as well as their supposed medicinal benefits. I have brewed a couple non-hopped beers (Heather Ale, and the Winter Kvass), but I have yet to brew one with the classic combination of herbs that make up gruit.  Martin and Marty both seem confident that these herbs (yarrow, sweet gale, wormwood, marsh rosemary etc...) have a stimulative effect compared to drinking a couple hopped beers (hops being a sedative). I haven't noticed much difference, but for more information of these herbs and their supposed effects you can read Stephen Harrod Buhner's Sacred and Herbal Healing Beers.

Martin and Marty buy their herbs in bulk from an online spice/herb shop for the most part. The only one of the mainstay herbs that is hard to come by is marsh rosemary, which they buy for $10 a jar from a Canadian who forages for it (Labrador tea was suggested as the best easily accessible alternative). They have also started to grow some of their own and forage for local equivalents.  The most important aspect of brewing a good gruit is avoiding over-spicing (as most of the handful of commercial examples I've tried have been), which is something that the various gruits they served (classic, sage, burdock root etc...) avoided. They are still tinkering with the timing, sometimes adding all of the herbs near the start of the boil, others saving the more aromatics herbs for a later addition.

Propane is so popular with brewers because it is clean, easy to control, and compact, but it also adds ~$4 a batch onto my cost. Brewing over a fire has a romantic appeal, it makes brewing seem more like an event and less like a chore. If you want to brew over a fire you'll need something to suspend the kettle over the fire and a way to adjust the heat. A more complex rig could have a winch to raise and lower the fire, but in Marty's case he simply pulls the kettles partway off the fire when they threaten to boil-over. Another advantage of brewing over a fire is that it is easy to brew a couple batches at once over a single fire (we brewed three 10 gallon batches). Building guitars for a living and having a house out in the woods Marty has a lot of extra scrap wood to burn, but if you didn't you'd probably lose most of your savings from not buying propane by buying wood.  Martin has a web page with details of his slightly more elaborate fire-brewing rig.

They do not get a smoky flavor from boiling over the fire, or any additional caramelization (or melanodins) from the intense heat as far as I tasted.  The soot from the fire does blacken the kettles, but this isn't a big deal.  The biggest disadvantage is that tending the fire to ensure that it is hot enough to boil the wort is one more thing to worry about.

To cool the beers they simply leave the kettles covered overnight before transferring the cool wort to carboys and pitching yeast the next morning. The wooden lids are not tight fitting, which allows ambient air to be sucked in as the wort cools and contracts.  As a result of this (and the lack of preservative hops) all of the beers I tried had a wonderful refreshing tartness that mingled surprisingly well with the herbal bitterness. Sour and bitter and not normally flavors that combine pleasantly, but it this case the bitterness comes through in the front with the sourness holding off until the finish.

It was a terrific way to spend a day, capped off with a delicious dinner of venison (which Marty had hunted) roasted in a pot over the same fire we were using to brew. Not sure that I'll be building a fire in my small backyard to brew anytime soon, but it certainly inspired me to try my hand at a traditional gruit.

Martin's Classic Gruit
10 gallons:
Mash 1/2 a bag (25 lbs) of American pale malt in the low 150s F (strike water ~165 F).

After 60 minutes of conversion, run-off, batch sparge, then bring wort to a boil.  They do not recirculate which leaves the beer hazy, and looking like a medieval beverage.

3 oz yarrow and 1 oz wormwood for bittering near the start of the boil.
1/2 oz each of myrica gale (sweet gale) and marsh rosemary (or Labrador tea) as finishing in the last 10 minutes of the boil.

Allow to cool naturally overnight.  In the morning rack to fermenters, pitch US-05, and allow to ferment.  When fermentation is complete prime and bottle.

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