A Dutch Beer Puzzle

Dutch Beer Puzzle – Kuit, Kuyt, Koyt, Kuite, Kuyte, Koyte, Koeyte, etc.
by Mike Retzlaff

In early 2014, The Brewers Association recognized Koyt as a Dutch beer style.  The CNB, (Campaign for Netherlands Beer styles), was quite pleased.  Koyt, the grandfather of all Dutch beer styles, was the most commonly consumed beer in Holland during the 15th and 16th centuries.  It is surely the basis for later beers.  For the last 15 years or so, there has been a resurgence in brewing of this style by home and commercial brewers alike; in the Netherlands and elsewhere. Much of this info has been distilled from Witte Klavervier; a website by Federick Ruis. The site is well worth a visit. It covers much more than Koyt.

I.  History

According to the research of Gerard Doorman; published in ca. 1955:
Hoppenbier = beer with hops; while Kuitbier = unhopped beer.  At the time the designations seemed important because of the difference in taxes levied on beer with gruit vs. hops.

In contradiction, the village of Gouda, in 1468, levied a hop tax on “Koeyte” beer.  Hops were used in the Belgian city of Leuven in “Kuit”.  Remember that a large swath of Belgium, mainly Flanders and Brabant, was under Dutch control until 1823.

Another researcher, Hans Ebbing, in the mid 1990’s, concluded that Doorman was a off in his interpretations of historical texts.  He had missed the point on the differences between hopped beer and gruitbier.  Gruit, various blends of herbs, was used before the common use of hops in beer brewing.  Gruit lost ground in brewing and eventually was completely replaced by hops.

In Leuven, gruitbier had disappeared by 1423. In 1427, a tax collector in Delft wrote that “people had stopped brewing with gruit long ago.”  In 1468, in Gouda, the same was stated that “gruytebier hadn’t been made for ages”.

The Reinheitsgebot of 1516, forbade the use of herbs in beer making thus ending the use of gruit in beer; at least in Bavaria.  This law was later extended throughout Germany and covers all bottom fermenting beer produced there today.

It is highly unlikely that Koyt was ever brewed with gruit; evidence leans toward hops only.

Kuit, Kuyt, Koyt (all with or without an “e” at the end) are various spellings of the same style.  As noted above, these beers were brewed in both the Netherlands and parts of present day Belgium.  It is assumed that the differences are due to there being no standardized spellings at the time.  Gutenberg didn’t invent his movable type press until 1440.  It still took some time for standardized spellings to take hold in all languages.  I’ll use the “Koyt” spelling and hope you don’t take personal offense.  (‘offence’ if you’re British – standardized or ‘standardised’ spelling?)  It’s their language and we’ve ruined it – you should see how I butcher Dutch.

Until the late 19th century, Koyt was the most commonly consumed beer in the Netherlands.  In trade, it rivaled beers such as Mumme brewed in Hanover and Braunschweig, Germany. It was a direct contender for the beers of Hamburg, too.

II. Parameters.

Koyt is a three grain beer and was generally made of oat malt, barley malt, and wheat malt in proportions of 3 – 2 – 1 respectively.  That equates to 1/2 or 50% oat malt, 1/3 or 33% barley malt, and 1/6 or 17% wheat malt; all by weight. 

The oats used in these early beers was a different cultivar than is grown today.  This early variety was lower in protein and glucans and was exported, even to England as “thick Dutch brew oat”.  As barley became the staple of brewing, brewers abandoned oats and relegated them to feeding draft animals.  Oats were then bred to be a better culinary grain instead of a brewing grain.  The “modern” varieties also have higher crop yields but now average about 15% protein content.

According to Derek Walsh (a contemporary brewer / researcher / beer judge) Koyt should fall within the following parameters:

OG – 1.050 to 1.080 s.g. (12.4 to 19.3 oP)
FG – 1.006 to 1.015 s.g. (1.5 to 3.7 oP)
Alcohol – 4.7 to 7.9% v/v
Hop bitterness of 25 to 35 EBU (same as IBU)
Color – 10 to 25 EBC (5 to 12.7 SRM)  Anything darker than 15 EBC (7.6 SRM) should come from a long boil and not the grist bill. These beers were normally boiled for 3 hours over an open flame.

III.  Brewing

Oats is a skinnier grain than barley and requires closer gap in the rollers of the grain mill.  The grain basically falls through the mill if set for barley or wheat.  My roller mill is non-adjustable so I overcame this problem by running the oat malt through a Corona mill which is a bit crude but it is adjustable and does an acceptable job.

Mash thickness is another factor to consider.  Research found a suggested mash thickness of 4L/kg. (1.92 qts/lb.) which is rather thin.  I’ve brewed this beer with 2.7L/kg. (1.33 qts/lb) with no problems at all.  The source admitted that the thinner mash was to lessen the possibility of the grist balling in the mash tun.  If you pour the crushed grist into the mash liquor, it is much less likely to “ball”.  The enzymes actually work much better with a thicker mash.

I’ve found a recommended mash schedule and include my modified mash regimen.

Recommended mash                           My mash
35 C for 20 min. (95 F)                       (this rest is pointless with this grist bill) 
45 C for 20 min.                                  113 F for 30 min. as a β-glucanase (cytolytic) rest
52 C for 15 min. (125 F)                     (marginal need at this proportion of oats)
62 C for 5 min.                                    144 F for 30 min.  as a β-amylase / maltose rest
72 C for 10 min.                                  162 F for 2 hr.  as a saccharification rest
78 C for 5 min.                                    172 F for 10 min.  as a mash out

My mash regimen will work fine even with a 100% malted oats grist bill.  I add some CellarScience Glucabuster enzyme to the mash as a little insurance and it lauters flawlessly.

Older noble hops such as Hallertau, Spalt, Saaz, Tettnang, or even E. Kent Goldings are to be preferred.  The finished beer should have some hop aroma.

A neutral ale yeast is suggested. (Wyeast 1007, 1056, 1338 – ferment at the low end of range)

I can’t find any conclusive parameters on carbonation other than “The beer must have at least a thin layer of stable foam.” (another Derek Walsh quote)  My guess is that it should be carbonated between 1.5 and 2.2 vol.

The beer may be slightly hazy in clarity but have no acidity or DMS.  Diacetyl at very low levels is acceptable.

Because oats is an oily cereal grain, keeping qualities aren’t what you’d expect in an all barley beer.  Not trying to make an “Oatywine” to lay down until “Tommy comes of age” would seem to be good advice.

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