Background
The use of Kveik yeasts has exploded these last few years. Kveik yeast strains are cleaned up versions of yeast cultures that have been used in traditional Norwegian farmhouse breweries for many years. They ferment fast, and can be used at higher temperatures without generating too many fusel alcohols. There are quite a few strains out there complete with flavour expectations, so we decided to put some of these strains to the test.
Method
A simple malt bill of 50% Pilsner and 50% Munich dark was used, with Magnum as the bittering hop. No other hop additions were made to focus on the yeast flavours. The wort was split into 6 bottles with different yeasts:
1) US-05 – neutral taste
2) Belgium yeast – fruity esters and spicy phenols
3) Kveik Rivenes – orange peel, citrusy
4) Kveik Lida – Apricot, stone fruit, white grapes
5) Kveik Stranda – Ripe tropical fruit, overripe pineapple, mango
6) SafAle WB-06 – a smooth ester and phenol flavour.
The starting gravity of the wort was 1.0445. Once the fermentation appeared to be finished samples of the beers were collected for analysis in the Quantos and the beers were bottled with 5g per litre of sugar and left to carbonate and condition for 2 weeks before the taste test.
Taste test
First things first, the taste – the 6 beers were given to our small panel of taste testers with the description of flavours that the yeasts should bring to the beer. The most popular yeast was the Kveik Lida followed by the Kveik Rivenes. The Belgium yeast also proved popular, the US-05 was considered neutral as expected, and the SafAle WB-06 was the least liked. However, this is probably an unfair use of the yeast as it meant for wheat beers and there was no wheat in the wort. Only one person correctly identified the Kveik strains, with most thinking the Lida had a pineapple flavour.
The Science Stuff
The results from the Quantos are shown in the table above. The Belgium yeast had the highest alcohol content with the Kveik Rivenes having the lowest. The Belgium yeast really chewed through the Free Amino Nitrogen (FAN) which is not surprising as it attenuated more than the other strains but interestingly the bitterness (based on iso alpha acids) decreased less than the other strains which decreased by approx. 10 points (or mg/l) between the wort and finished beer as expected.
In the next blog, we will compare the flavour profiles from different sugars added to a wort.
Thank you for reading the first of what we hope to be many blogs investigating the brewing process of beer, the fermentation of wines, country wines, ciders, meads and all the interesting drinks that fall somewhere in between. If you have any comments or you would like to suggest something to investigate get in touch with us at: brewingdeconstructed at qfood.info