Author: James Ewen, Head Brewer & Co-Owner
With the release of our newest IPA, Minnesota Might, I thought it was time to pull back the curtain a bit and explain some details of the brewing process at Wooden Hill. It’s also a good opportunity to highlight some other local companies putting their own stamp on the craft market. With their ingredients, I was able to brew a beer using 100% Minnesota malted barley and Minnesota grown hops.
Before I get ahead of myself, here’s a broad strokes breakdown of what it takes to go from an idea of a new beer, to having that finished beer in a glass: formulate the recipe, order the ingredients, brew the beer (really broad strokes here), ferment and mature, cool and carbonate, keg and tap.
Considering the amount of ingredients at the disposal of any 21st century brewer, whether professional or not, it can seem like a good use of resources to bulk up a recipe with a few different base malts, several specialty malts, and a half dozen hop varieties, not to mention the plethora of sugars, fruits, spices, and flavoring extracts that are available. It can seem like a good idea, and that may indeed be the case for some beers, but I like to keep things simple.
The bulk of the ingredients in a recipe is the grain. In our case, it’s malted barley. Considering that beer is 90-95% water, a high-quality base malt is important. For this recipe I chose to use only one variety for the entire grain bill, Maltwerks Pale Malt.
Maltwerks is a small malthouse out of Detroit Lakes, MN. I first experimented with their pale malt late last year with the release of Snowburst Juicy IPA. I’ve since implemented the same malt as the base for multiple one-off IPA releases. I’ve found that it can stand up to heavily hopped beers without asserting itself too much. An excellent base from which to build on.
Let’s talk hops. Just like malted barley there are numerous varieties, and not all are created equal. However, in the case of hops it’s a little more complicated than that.
The same variety grown in two different regions can smell and taste completely different from one another. Even one crop year to the next grown in the same place can vary. That’s why I was intrigued when Mighty Axe Hops reached out with samples of their varieties grown in Foley, MN. I chose to use three of their varieties in this IPA recipe, Cascade, Centennial, and Zeus.
I rounded out the ingredient selection by choosing a neutral American yeast strain that would allow the other flavors to shine.
Now we’ve got our ingredients listed, choosing when to add them and at what temperatures is next. I went with a single infusion for the grain, mixing all 550 lbs with hot water to create a mash that settled around 152F. The essential enzymes in the grain are activated in this temperature range and start chopping up the starches in the grain into complex and simple sugars.
At Wooden Hill, our mashing process is similar to most small breweries. The grain is loaded into a mill, crushed, and transferred into a flex auger system that pulls the grain up above the mash tun and drops it into the vessel through a grist hydrator.
The grist hydrator is made up of a series of holes in a tube within a tube that act as water jets as hot water is pushed through them at a high rate. Simply put, by the time the grain falls through the grist hydrator and into the mash tun, it is no longer dry but rather the consistency of oatmeal.
For the entirety of the mashing process we use a mash paddle to stir and keep an even consistency in the grain bed.
After mashing in is complete, the mash is left untouched for an hour so the enzymes can convert the starches to sugar.
Once the mash has had time to rest, the lautering process begins, which for us is two steps; vorlauf and sparge. The vorlauf is when the wort (the sugary liquid is now called wort) is drained from the bottom of the mash tun and pumped back up to the top of the grain bed. This establishes a natural filter bed, and within 20 minutes or so the wort runs clear.
Once the wort is clear the vorlauf ends and we begin pumping the wort into the boil kettle. This begins the sparging process, as fresh hot water is sprayed over the top of the grain bed to start pulling out the leftover sugars in the grain.
Sparging lasts anywhere from one to two hours in our case. We stop when we’ve collected about 11 barrels (341 gallons) of wort in the kettle.
The kettle is heated by an indirect fire system. There is a firebox hooked up to the back of the kettle that blows extremely hot air into the jacket around the kettle. This brings us to a nice rolling boil.
By the time we’ve hauled all of the spent grain out of the mash tun (which is then composted or donated for use as animal feed), the boil has begun.
For this IPA recipe I chose to add all of our hops at flame out (the end of the boil). While this may not give the same results on a small scale, in our case the hops will be steeping in very hot wort for at least half an hour if not longer before the wort is cooled.
Bitterness is extracted from the hops at this high temperature and is the right amount to prevent the finished beer from being too sweet.
I went with about a pound of hop pellets per barrel of wort of Cascade. Once the wort stopped boiling, the whirlpool process began. By pumping hot wort from the bottom of the kettle through the valve in the side of it, a gentle whirlpool forms inside the kettle.
This helps all the hops and other trub compact into a cone shape at the bottom of the kettle. This is an important step as it prevents large debris from clogging up the heat exchanger in the next step.
After ten to fifteen minutes of whirlpooling and another fifteen minutes of allowing the wort to rest with no movement (again so debris will settle to the bottom), we begin to knockout.
Knockout is when the wort is sent into the fermenter through a heat exchanger, which knocks the wort down to room temperature using a series of plates. Hot wort is pumped in one end of the heat exchanger and cold water is pumped into the other end. The two liquids exchange their temperatures as they pass through the plates. Cool wort exits on one end and is sent to the fermenter while hot water exits the other end and is sent into the Hot Liquor Tank (fancy name for a hot water tank, all water used in the brewing process is referred to as ‘liquor’) to be used in the next batch of beer.
The heat exchanger is affixed with a gas inlet so we can trickle in pure oxygen as the wort passes through. The right amount of infused oxygen is a key for healthy yeast activity.
Knockout takes about an hour, during which time we monitor the wort temperature, flow of oxygen, and usually get up on a ladder and add the yeast into the wort.
Once all the wort is in the fermenter we all grab a beer, cheers, kick back and celebrate a job well done… okay, that’s a lie. There’s actually a fair amount of clean up involved. We also brewed the same beer the next day to combine with the first batch. Let’s just skip to the next fun part:
Fermentation and Maturation
Over the next several days, the yeast works furiously eating the sugar in the wort and producing carbon dioxide and alcohol. A glycol jacket around the tank allows for precise temperature control to keep the beer from overheating due to the activity of the yeast.
For this recipe I went with three dry hop additions. The first was Centennial, then Cascade a few days later, then Zeus once fermentation had ended. After crashing the temperature down to 38F, the beer was transferred to a brite tank, where it was kept cold and force-carbonated.
Once kegged and on tap, we were finally able to pull a pint and get a taste of the finished product. I could add some tasting notes, but I think it’s more fun to come on by and experience it for yourself!