http://www.garshol.priv.no/blog/ Personal blog of Lars Marius Garshol. en larsga@garshol.priv.no (Lars Marius Garshol) larsga@garshol.priv.no (Lars Marius Garshol) http://www.garshol.priv.no/blog/438.html?utm_source=rss&utm_medium=web&utm_campaign=rss It's commonly said that "gruit is the beer that was brewed before people started using hops," and it's fascinating how many errors there are in that short, simple sentence. Gruit is one of the most misunderstood areas of beer history, one that even professional historians have messed up, so here is an attempt to clear up the worst confusions. larsga@garshol.priv.no (Lars Marius Garshol) 2026-05-18 20:01:00 CET http://www.garshol.priv.no/blog/442.html?utm_source=rss&utm_medium=web&utm_campaign=rss This is the third blog post on the new Verstrepen lab paper on farmhouse yeast. While we were working on it we thought the family tree showing that kveik, gong (Eastern Norwegian farmhouse yeast), and Baltic farmhouse yeast were all one big family was going to be the headline result. As it turned out, the paper by Richard Preiss et al, came first. Still, it's nice to see that these two papers agree. larsga@garshol.priv.no (Lars Marius Garshol) 2026-05-03 13:59:00 CET http://www.garshol.priv.no/blog/441.html?utm_source=rss&utm_medium=web&utm_campaign=rss The new Verstrepen lab paper on farmhouse yeast (blog post introducing it) gives us a level of insight into these cultures that we've never had before. And one of the things it gives us is a much stronger handle on is exactly how many strains there are in each farmhouse yeast culture. (If you don't know what I mean by farmhouse yeast, see this example.) larsga@garshol.priv.no (Lars Marius Garshol) 2026-04-12 11:48:00 CET http://www.garshol.priv.no/blog/440.html?utm_source=rss&utm_medium=web&utm_campaign=rss A new major paper on farmhouse yeast has just been published, which gives more insight into what's in a farmhouse yeast than we've ever had before. If you're not familiar with it, farmhouse yeast is yeast that has been reused by people brewing in the farmhouse tradition for so long that it's adapted to being used in that type of brewing. larsga@garshol.priv.no (Lars Marius Garshol) 2026-04-06 21:24:00 CET http://www.garshol.priv.no/blog/439.html?utm_source=rss&utm_medium=web&utm_campaign=rss Michael Jackson famously classified beer into ale and lager based on how it was fermented, but this is a rather superficial feature. What defines beer and sets it apart from other alcoholic drinks is that it's made from grain, which contains no sugar. Making mead from honey, cider from apples, or wine from grapes is far simpler than brewing beer, because the sugar is already there. With beer, however, you need to convert the starch to sugar first, and the need for this step is what defines beer as a drink. larsga@garshol.priv.no (Lars Marius Garshol) 2025-12-03 15:35:00 CET http://www.garshol.priv.no/blog/436.html?utm_source=rss&utm_medium=web&utm_campaign=rss Six years ago, the paper that told us where kveik came from was published. In my mind, the immediate question to ask after that was: what about the farmhouse yeast that was not from Western Norway? Where did that fit? Luckily for me, and you, the same question occurred to Richard Preiss and Kristoffer Krogerus, two of the researchers behind that kveik paper, and the same year they started working to find out. Yes, in 2018. larsga@garshol.priv.no (Lars Marius Garshol) 2024-04-07 14:47:00 CET http://www.garshol.priv.no/blog/435.html?utm_source=rss&utm_medium=web&utm_campaign=rss I was doing a talk about kveik in Oslo, when one of the audience members afterwards said that in his home village people also had their own yeast, but they called it "berm". This, he said, was in Atrå, a small place in upper Telemark. Looking at the map I found that it was indeed very small, and as high up as you can get before the central mountain plain where nobody lives. larsga@garshol.priv.no (Lars Marius Garshol) 2024-04-03 21:09:00 CET http://www.garshol.priv.no/blog/434.html?utm_source=rss&utm_medium=web&utm_campaign=rss One of the biggest mysteries in the history of beer is where and when people started using hops in beer. We still don't really know the answer, but we do know some things, and what we know is quite different from the history of hops as most people understand it. So I wanted to straighten out the record a little bit. But before we get into that, let's set the context. larsga@garshol.priv.no (Lars Marius Garshol) 2022-12-06 10:15:00 CET http://www.garshol.priv.no/blog/433.html?utm_source=rss&utm_medium=web&utm_campaign=rss Martyn Cornell has been fulminating against what he calls The Great Medieval Water Myth: that the peasants drank ale all the time because ale was safe to drink while water was not. He concludes that it's wrong, and that English peasants mostly drank water. larsga@garshol.priv.no (Lars Marius Garshol) 2022-10-15 11:57:00 CET http://www.garshol.priv.no/blog/430.html?utm_source=rss&utm_medium=web&utm_campaign=rss In March 2021 Norwegian archaeologists posted the photo above on Facebook, asking their followers what they thought these planks might have been used for. The planks had been found during an archaeological excavation in the centre of the Norwegian city of Trondheim in the 1980s, but nobody had ever figured out what they had been used for. The planks were thought to date to the 12th century. larsga@garshol.priv.no (Lars Marius Garshol) 2022-10-01 12:54:00 CET http://www.garshol.priv.no/blog/432.html?utm_source=rss&utm_medium=web&utm_campaign=rss I just sent to the publisher my academic book on Norwegian farmhouse ale, which summarizes what I've found in nine years of research on the subject. The text I sent is in Norwegian, but I may be able to get it translated into English. The English-language publisher wants to judge interest before they decide, hence this blog post. So if you're interested in that, read on to the end. larsga@garshol.priv.no (Lars Marius Garshol) 2022-09-15 13:33:00 CET http://www.garshol.priv.no/blog/429.html?utm_source=rss&utm_medium=web&utm_campaign=rss As I wrote last year I quit my job as a software engineer to have more time for writing books and doing research, even though I suspected that economically that might be a less than optimal decision. In practice it's worked out as I thought: I did get more time for writing and research, and a lot less money. larsga@garshol.priv.no (Lars Marius Garshol) 2022-05-10 13:05:00 CET http://www.garshol.priv.no/blog/428.html?utm_source=rss&utm_medium=web&utm_campaign=rss I left my hotel, crossed the river, and headed for the outskirts of town. Eventually I passed out of the town entirely, into the countryside. And there, in the middle of an empty field, stood a huge, modern extraordinary-looking glass building. It seemed to change shape depending on which angle you looked at it from. larsga@garshol.priv.no (Lars Marius Garshol) 2022-02-26 20:20:00 CET http://www.garshol.priv.no/blog/425.html?utm_source=rss&utm_medium=web&utm_campaign=rss The day after we visited Finlandia Sahti the time had come for Lammin Sahti, the other major commercial producer of Finnish sahti. The name really means "sahti of Lammi", or "Lammi's sahti", and the brewery is on a small farm in the county of Lammi, about 100 kilometers north of Helsinki. (This was part of the Finnish sahti expedition of 2018.) larsga@garshol.priv.no (Lars Marius Garshol) 2021-11-15 14:24:00 CET http://www.garshol.priv.no/blog/427.html?utm_source=rss&utm_medium=web&utm_campaign=rss A recent archaeological find caused much stir and writings in various newspapers, but everyone seems to have missed the most interesting part of the discovery. However, before we get to that, let's have a little look at the context. larsga@garshol.priv.no (Lars Marius Garshol) 2021-11-01 08:59:00 CET http://www.garshol.priv.no/blog/426.html?utm_source=rss&utm_medium=web&utm_campaign=rss A few years ago I wrote about the groundbreaking study (Gallone et al 2016) that for the first time gave us an idea of how the different types of brewers yeast are related to each other. It was progress in genetic technology that made the study possible, and in the years after more studies have come out, giving us an even better picture of the family tree of yeast. So I figured it was time for an update. larsga@garshol.priv.no (Lars Marius Garshol) 2021-10-26 10:39:00 CET http://www.garshol.priv.no/blog/423.html?utm_source=rss&utm_medium=web&utm_campaign=rss When Richard Preiss first started studying kveik his former thesis advisor at the University of Guelph, George van der Merwe, told him that it was a "super-yeast" because of its speed and stress resistance. The lab that van der Merwe heads at the university has been investigating how yeast responds to stress for many years, and that made them extra excited about kveik. Since kveik was so robust, maybe it knew some special tricks for handling stress? larsga@garshol.priv.no (Lars Marius Garshol) 2021-08-01 13:49:00 CET http://www.garshol.priv.no/blog/421.html?utm_source=rss&utm_medium=web&utm_campaign=rss Finlandia Sahti is a commercial brewery making sahti way out in the Finnish countryside, roughly midway between the towns of Pori and Tampere. It's really a farm that's been turned into a commercial brewery by installing a brewkit and setting up a small bar. We park in the yard, where we're met by Petteri Lähdeniemi, the brewer and brewery owner. (This was part of the Finnish sahti expedition of 2018.) larsga@garshol.priv.no (Lars Marius Garshol) 2021-06-27 12:17:00 CET http://www.garshol.priv.no/blog/422.html?utm_source=rss&utm_medium=web&utm_campaign=rss A good while ago some reader suggested that I should publish this blog as a book for people who want to actually read through the whole thing in sequence. And it's not a bad idea, because finding the beginning and then stepping through it, skipping the stuff that's not about farmhouse ale, is a little awkward. But back then I didn't really have time for it, so I didn't do it. larsga@garshol.priv.no (Lars Marius Garshol) 2021-06-19 14:01:00 CET http://www.garshol.priv.no/blog/415.html?utm_source=rss&utm_medium=web&utm_campaign=rss We drove along dirt roads through seemingly empty forest for half an hour, the dust curling lazily behind us. Eventually we turned onto a road with a sign saying Viherojantie, "Viheroja road." That meant we were getting close, because we were going to brew with Olavi Viheroja, who lives on the farm with the same name, and the road was named after the farm. (This was part of the Finnish sahti expedition of 2018.) larsga@garshol.priv.no (Lars Marius Garshol) 2021-05-22 13:26:00 CET