Crispy Brewing with Kveik: Mind the pH Gap

Yes, another post about kveik. We promise the next few blog posts will cover other topics like new Brett strains, yeast nutrition, and food fermentations instead. 

Introduction 

While kveik yeast burst onto the scene with promises of fruity, high-temp, high-octane ferments, it has also found a surprising home as the yeast of choice by some brewers for clean and crisp, easy-drinking beers. When kveik is handled like 'normal yeast', with a standard pitch rate and temperature regimen, it often produces quite clean and neutral flavour profiles, with the added benefit of the rapid kveik yeast ferment. 

However, for every kveik lager success story, there is another report of someone with thin or otherwise underwhelming beer. We're starting to understand the reasons for this, and working with brewers to determine the best ways to brew with kveik to hit the target each time. 

Yeast impact on beer pH

pH is critical throughout the brewing process, from the water that is used to hydrate the mash through to the finished beer. Nearly every ingredient plays a role in modulating beer pH. The water contains minerals that determine the degree of pH buffering. The colour and amount of grain influences the pH during the mash. Hops, too, can influence pH, especially during dry hopping where the pH may raise by up to 0.3 units.

The same is true of yeast. Some yeasts drop pH more than others. Following reports of low final beer pH from brewers including Long Beach Beer Lab's Levi Fried and others on the Milk The Funk group, we made sure to include testing beer pH in a massive screen we are running to compare all of our yeast strains.

 

Terminal pH of miniature fermentations from a large screen conducted by Iz Netto. Ferments were performed in triplicate. Only strains from the 'British', 'Kveik' and 'Lager' groups were selected for this article. The grey background shows the strains compared to all strains in the study. 

What we see here is that kveik does indeed drop pH more than the average yeast, and certainly more than English Ale yeasts and Lager yeasts, categories which tend to produce the least acidic final beer pH. This has implications for flavour, as low beer pH is sometimes associated with perception of a thinner body as well as harsher and more astringent hop character. It is quite fascinating that despite kveik being used in many of the same styles as the Lager and English strains ("lagers", and NEIPAs respectively), they do produce beer with noticeably different terminal pH. 

These data present a possible solution: when brewing with kveik, especially when targeting a crisp and clean beer, it can be helpful to use water with higher buffering capacity (mineral additions). It can also be helpful to avoid wort pH that is too low. While targeting 5.1-5.2 pH may be perfect for a Helles fermented with lager yeast, the same wort may end up producing a slightly too acidic and thin beer in the hands of kveik. Pushing that wort pH to 5.4-5.5 may help improve the final sensory characteristics of the beer.

This also may explain why Escarpment Labs, being in Guelph with hard-as-nails water, hasn't seen too many challenges with making kveik beers while others with softer water have seen larger pH challenges. 

All this being said, different brewers have seen different results. For example, Matt Duimering at Reverence Barrel Works has been using a wort pH of 5.1, while Levi Fried at Long Beach Beer Lab has been shooting for the higher end of the pH range. Either way, experimenting with wort pH for kveik beers can be a worthy experiment for brewers looking to get the most out of these fascinating yeasts. 

Other Fermentation Parameters 

Pitch Rate: Kveik pitch rate can impact the resultant flavour profile, however this is strain/blend dependent and more study is required. Generally, we recommend "standard" pitch rates of 0.7-1 million cells / mL / °P for a neutral flavour profile and rapid fermentation. 

Temperature: For clean ferments, we typically recommend anywhere between 15-20ºC, which still yields a rapid ferment with kveik but with less intense esters. 

Nutrition: Another important parameter of kveik that we will discuss in detail in the future is nutrition. In general, we find that kveik require at least 180ppm of FAN, compared to lager yeasts which routinely use about 30% less FAN. This means that a low gravity, all-Pilsner malt wort may be insufficient in FAN and result in sulfury off flavours or stalled ferment in the hands of kveik. If you are brewing wort below 1.060/15ºP, we recommend adding a yeast nutrient. 

Recipes/Examples 

We reached out to some of our partner breweries to ask them about their process and experience in brewing crispy beers with kveik: 

Burdock Brewery, Matt Park - Lunjbier

The Lunjbeer we wanted to make something relatively low abv, medium+ bitter, with a nice noble hop character. It started at 9.7P and attenuated to 1.7P (it definitely creeped down after dry-hopping at around 3P). I was really happy with the way this beer turned out - it was truly a crispy boi. 

Yeast

Hornindal Kveik Blend, 6 hL pitch into 12 hL wort.

Grain

The beer was a blend of three pilsner malts (barn owl, best, gambrinus) - 9.7P starting grav.

Hops

Bittered with Columbus, Strisselspalt, Hallertau Blanc, with some Citra at flameout  - 30 IBU
Dry-hopped with Tettnanger  (80g/HL) and Helga 225 (g/HL) - 3 days into fermentation 

Water

Bit of CaSO4, CaCl2 to bolster the Toronto water profile, with bonus pinch of NaCl (about 50g in 14.5HL of wort)

Reverence Barrel Works, Matt Duimering - Hornindal Kveik Lager

OG 1.045  |  FG 1.008  |  IBU 17

Grain bill: 

  • 65% pils
  • 10% Munich
  • 25% cane sugar (I like a dry lager)
  • a pinch of roasted barley for colour

Mash:

Keep calcium between 50-100ppm 
Mash pH of 5.1

Mash in at 125ºF and rest for 30 min
Raise to 148ºF and rest for 60 min
Raise to 168ºF, hold and vorlauf until the wort is crystal clear.

Hops:

Single hop charge of magnum as a FWH addition
Use anti foam during hot break
Boil vigorously
Add whirfloc 10 min before end of boil
Transfer clear wort over to FV

Yeast:

Pitch Escarpment Hornindal Kveik Blend at regular ale pitching rates at ~20ºC.
Ferment for 7-8 days then crash, carb and serve.

Long Beach Beer Lab, Levi Fried - General Suggestions  

  • Brewing clean lager-like kveik beers start with brewing super clean lager-like wort
  • We recirc the mash to clean it up and produce a vigorous boil
  • The entire time, I am measuring pH
  • I use a higher salting ratio to put my pH in the 5.4 - 5.5 range and also add buffering capacity to my wort
  • We notice considerable pH drops during kveik fermentation
  • I'm using RO water and 400g caso4, 100g cacl2 and 100g Ca(HCO₃)2 for a 10bbl batch
  • I have used dextrin malts to improve body
  • We produce clean blondes and lager beers with Skare and Oslo in as little as 3 days grain to glass 
  • We use a brite tank, biofine during, transfer, and carb during fining.