Cooking with Kveik yeast: Lutra Kveik pizza
Background and introduction:
Using brewers yeast to make food is nothing new. For millennia, brewers yeast and bakers yeast may have been interchangeable; before the industrialization of beer brewing, beer brewed at home was likely fermented with the same yeast that was used to make bread and other fermented beverages (fermented grapes, rice, etc). Even today, many brewers yeasts are very closely related to bakers yeast and difficult to distinguish at the the phylogenetic level (Press et al., 2018, Fay et al., 2019). Ale brewing yeasts have a mixed ancestry, are phylogenetically diverse, are not clearly separated from bakers yeast, and reflect use throughout human history. Some beer styles, like Finnish Sahti, are still traditionally made using bakers yeast (https://dev.bjcp.org/style/2015/27/27A/historical-beer-sahti/). There may in fact be little distinction between bakers and brewers yeasts, especially in farmhouse brewing tradition (https://www.garshol.priv.no/blog/411.html).
Kveik yeast are a genetically distinct and "thermotolerant" strain of ale yeasts (Saccharomyces cerevisiae) hailing from Norway and have been used in traditional Norwegian farmhouse brewing culture for generations. There is a lot to say about kveik that I won't get into here (see the famous Lars Blog for more info https://www.garshol.priv.no/blog/), but kveik yeast strains are growing rapidly in use and popularity around the whole world. Many other beer bloggers, bakers, and brewers have made food using brewers yeast, so I thought I'd give it a try using leftover Kveik yeast (at least two other examples I'm aware of are https://pastrychefonline.com/baking-with-brewers-yeast/ and http://humebrew.com/making-bread-with-beer-yeast/).
Methods:
I brewed a 4.8% ABV pseudo-pilsner beer (recipe at the bottom) using Omega Lutra Kveik (https://omegayeast.com/yeast/norwegian-kveik/lutra-kveik) and had lots of leftover yeast. I was inspired to use the yeast to make pizza dough. The pizza recipe I use is inspired by the Corleone Family Cookbook (which my wife received as a gift from her aunt) and it calls for 2 teaspoons of dry yeast, which according to (https://www.thecalculatorsite.com/cooking/teaspoons-grams.php) is ~9.4 grams. A typical dry yeast pack for brewing 5 gallons would be ~11 g of dry yeast. On this page (http://hanseata.blogspot.com/2012/05/my-pantry-all-about-yeast.html) it is recommended to use 2x the amount if you use fresh yeast instead of dry yeast (= 22 g). Of course, I tripled that and used ~60 grams of fresh yeast because at least some of what I harvested from the beer was dead yeast and lees (precipitated protein, hop matter, and other garbage that settles to the bottom of your fermentation vessel during brewing).
The 12L fermenter had about ~1cm or so of settled yeast at the bottom and yielded about 300 g of solids (yeast + proteins + hop matter, etc). I thought I'd get more from the fermenter but one doesn't need much for baking and the low yield makes sense given the small volume of the fermenter. I should note that I would never store yeast like this for brewing, this yeast was intended only for baking.
I weighed out ~60 grams of harvested yeast and added 1.5 cups of water at 25 C (a temperature I know Lutra likes) and 2 teaspoons of sugar.
I waited about 10 minutes and noticed that the yeast/water/sugar mixture was already very active and bubbling. I should point out here that the harvested yeast had been in the fridge for 2 days before use.
I added 5 cups of bread flour and 1 teaspoon of salt to the water/yeast/sugar mixture. Then, I mixed it all well and kneaded into a bread ball and drizzled some olive oil on top. I let the dough ball sit, covered, for 1 hour near the preheating oven to keep warm. The dough ball doubled in size over the hour.
I then cut the dough ball in half, punched it down to get some of the gases out, and kneaded each half on a lightly floured surface until the dough was ready. I rolled out each dough ball into a roughly square shape and put some olive oil on the crust. I then let the rolled out dough rise for another hour at room temperature.
After rising for another hour, the rolled dough was ready to be topped and baked! We decided to make a very simple barbecue chicken pizza: BBQ sauce half mixed with red pizza sauce, grilled chicken, bell peppers, onions, and a 1:1 mix of cheddar and mozzarella cheese. We baked at 500 F (~250 C) for 15 minutes, but your oven may produce slightly different results so just watch the pizza and take it out once the crust is golden brown!
Tasting notes:
The pizza turned out reasonably well and noticeably different than usual. The crust was a bit firmer (normally I use 1 packet of instant dry yeast) and drier (maybe due to excess protein?). The crust also puffed up and rose more than usual, also perhaps caused by my eagerness to use as much kveik as possible. There was also a noticeable hop flavour and bitterness present; it was unusual but not unpleasant. There was evidently some hop matter that had settled to the bottom of the FV and made it into the dough - a bonus! Perhaps if the beer was a double IPA it would have made it even more interesting.
Recipe for the pizza:
1.5 cups of warm water (~25 C)
2 tsp of sugar
30-40g of kveik slurry
5 cups flour
1 tsp salt
2 tbsp olive oil
favourite toppings
Mix water, slurry, sugar and let sit at a warm temp for 10 minutes to activate
add 5 cups of flour, mix, and knead into a dough ball. Drizzle dough ball with EVOO
Let dough ball rise covered in a warm spot for 1 hr (or until dough ball doubles in size)
Punch out gas, cut in 2, and knead on a flour covered surface until ready
Roll out dough and let rise (covered) for another hour
Put a bit of EVOO on the crust
Add your favourite sauce and toppings
Bake at ~500 F (~250 C) for 15-16 minutes or until golden brown
Enjoy with a pint of your favourite kveik fermented beer!
Recipe for the beer which produced this Lutra kveik slurry:
75% Pilsner malt
20% Vienna malt
5 % Carapils
OG ~ 1.045
FG ~ 1.008
ABV: ~4.9%
Boil for 60 min
24 IBU of Hallertau Magnum at 60 min
0.7 IBU (1.6 g/L) of Hallertau Mittelfrueh at flameout
Chill to 32 C and pitch 1L starter (for up to 5 gallons)
Ferment at 32-35C until done (~3 days)
References:
1. Preiss, R., Tyrawa, C., Krogerus, K., Garshol, L. M. & van der Merwe, G. Traditional Norwegian Kveik Are a Genetically Distinct Group of Domesticated Saccharomyces cerevisiae Brewing Yeasts. Front. Microbiol. 9, 5412 (2018).
2. Fay JC, Liu P, Ong GT, Dunham MJ, Cromie GA, et al. (2019) A polyploid admixed origin of beer yeasts derived from European and Asian wine populations. PLOS Biology 17(3): e3000147. https://doi.org/10.1371/journal.pbio.3000147