Brewing your own vossaøl

<< 2014-09-22 17:08 >>

The gear

To better understand why vossaøl tastes the way it does I wanted to try to brew it with modern homebrewing equipment. So I teamed up with my friend Geir Ove Grønmo, who is an experienced homebrewer and had all the equipment we needed. The recipe is simplicity itself: pure pilsner malts, some noble hops, kveik (yeast). The biggest challenge is that the whole process takes so long.

The first step was to find juniper. Where is there juniper near Oslo? I had no idea, but internet searching told me it should be here. One evening when I was alone with my daughter we went into the forest to a place where she said there would be juniper. On the way we learned that she (being 6) had no idea what juniper looks like. Still, I had no idea where to look, so we might as well look where she suggested. And after about 20 minutes we did find one small bedraggled bush. It was so scrawny I didn't want to use it, but after searching another 5 minutes I found one that was just barely usable. Enough to fill up a small plastic bag with juniper.

Yeast starter

The second step was to grow the kveik (yeast). I had a small 50ml bottle I got from Sigmund, but this wouldn't be enough for our 20-litre batch. Geir Ove has a magnetic stir plate, so I gave him the yeast a few days in advance, and he was able to grow a good starter culture for us. He grew in two steps: first with 500ml yeast nutrient for 3 days, then with 1500ml for a little over a day. At the end of this we had about 0.1 liter of slurry at the bottom of the flask.

Making juniper infusion

With that out of the way, we were ready to start. First, we made juniper infusion for the mashing. That is, we put juniper branches into the kettle, then heated the water to about 85C. At this point it became obvious why Sigmund was using a sieve. The infusion was full of all kinds of dirt, including a ladybug. We fished out a good deal of it using a kitchen sieve, but there was no way to get it all.

Infusion with ladybug

Anyway, once the water was heated, we were ready to mash. Traditionally, the farmhouse brewers use juniper branches at the bottom of the mashtun, to act as a filter. Geir Ove's mash box already has a filter, but we threw a branch in there anyway, to stay as close to the traditional approach as possible. We poured on hot juniper infusion until the temperature was 68C, threw in half the hops, stirred a bit, then closed the lid and let it sit. In Voss brewers mash 3-4 hours, but we didn't have time for that, so we waited about 1.5 hours, then opened the lid so the temperature could drop. After another 30 minutes the temperature was down to about 58C, and we stopped.

The mash

Next step: the running. The traditional way to do this is excruciatingly slow, but we didn't have to worry about clogging the outlet, so we just ran it off very quickly. To get enough wort we poured more hot juniper infusion into the mash. Eventually we had about 40 liters of wort, at an OG of 1041. Then it was time for the boil.

Ready to boil

At this point, tradition calls for a wood-fired copper kettle, but we didn't have that. Instead, we used electric heating and a steel kettle. Where we did follow tradition was in the length of the boil: 4 hours, boiling away fairly exactly half the wort. After the mashing a lot of the dirt in the wort was gone, and during the boil we used the sieve to remove "the headache" (that is, the coagulated protein on the surface) and any remaining dirt. 15 minutes before the end we added the other half of the hops. At the end of the boil all the dirt was gone, and we had a clean wort with an OG of 1081.

Pitching

Then it was time for the kveik. True to tradition, we started by tasting it. It was very watery, but there was the familiar orange peel and spice flavour. No sign of acidity, or other problems. Before pitching we used Geir Ove's home made wort cooler to cool down the wort. Usually Geir Ove pitches the yeast at 20C, but now we were going to do it at 40C. As it turned out, the temperature fell of quicker than expected, and by the time Geir Ove had found his thermometer the wort was down at 35C.

Insulated fermenter

We pitched anyway, and put the fermenter in the bathroom, since that was the warmest room in the house. To help keep the temperature up we wrapped the fermenter in a camping mat, and put a fleece sweater on top. Under the sweater, on top of the fermenter, Geir Ove put a thermometer to keep track of what happened. The results are in the table below.

After fermentation (note trub at bottom)

We brewed on Sunday and pitched Sunday evening. By Tuesday night most of the fermentation was done, as you can see from the table. We stuck to tradition and bottled and kegged the beer on Thursday evening. Which is crazily fast. Geir Ove had brewed a double IPA at the same time on Sunday, and when we bottled the vossaøl the IIPA was still bubbling away. Kveik, fermenting 20 degrees warmer, is a fast worker.

Anyway, since we tapped the beer with a hose the slurry at the bottom was undisturbed. Thus, we could use a ladle and a funnel to transfer the slurry into more 50ml bottles and a couple of bigger glasses. And thus we had another generation of kveik, and I could fulfill my promises of sharing kveik. What we were doing was really microbiology, an operation professional breweries use labs and microcopes for. For us a funnel and a ladle would have to do.

So far I've tasted the result twice. Once a week after bottling, and once two weeks after. It's hazy and pale, unsurprisingly, with no real head, since there's no carbonation. The aroma is fruity yeasty Christmas spice, with traces of juniper. The taste is sweetish mealy juniper and oranges with Christmas spice notes. There's a kind of mealy, minty, grainy quality to it that I really enjoy, and the juniper flavour mixes in with the oranges just right. It's very well balanced, and easy to drink. The 8.8% alcohol is not really noticeable. Overall an excellent beer that stands up well in comparisons with commercial beers. I'm not ashamed to say this, since I neither wrote the recipe, nor brewed the beer. I simply helped Geir Ove as we replicated Sigmund's recipe as exactly as we could.

Kveik

The big question, of course, is how it compares with Sigmund's beer. I will find that out on Thursday, when I'm going to taste a bottle of his beer next to a bottle of the beer we brewed. More details then.

The day after we brewed the beer I was walking home from the train station after work, when my nose suddenly caught a familiar aroma: juniper! I looked around and quickly spotted a big circular hedge of juniper, right in the middle of a roundabout. I've walked past it every day for about four years, but never noticed. Not that it's much help: that roundabout sees such heavy traffic it would be suicide to venture out there.

Recipe

More details on the recipe:

• Juniper branches.
• 7.5 kilos of pilsner malts for 20 liters of wort (after boiling).
• 30 grams of Saaz hops
• 25 grams of Hallertauer Mittelfrüh
• OG after mash 1041, after boil 1081.
• Pitch at 35C (by accident, should have been 40C). Fermented for four days.
• Kveik yeast is essential.
• FG of 1014, giving an ABV of 8.8%.

If you want even more detail you can see the recipe on BeerCalc.

Anyway, the conclusion is that you can brew a passable imitation of vossaøl fairly easily, provided you have the yeast. I'm hoping to make that available via The Yeast Bay, after tips from people on Reddit. More on this later.

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