Media Center

The CBW Archives

Behind the beer: slapgan

Not everyone who likes beer is a brewer. That’s fine! And even those who have gone moderately far down the rabbit hole that is good beer know every little bit about the brewing process. This was highlighted for me by a Twitter conversation earlier this week, and so I realized I could take some time to explain one of the steps that happens towards the end of the process, during fermentation: slapgan.

Slapgan either gets pronounced sort of like “slap-gun” or “slap-gin” depending on the brewer: it’s a bit like hard-g gif vs the wrong way to say it. It describes the process of reading aloud to the fermenting beer.

Some brewers have a set book or story they read to a specific beer each time, but most just use whatever they’re currently reading at the time. It dates back to before people knew about yeast, and so it probably started as a way to try and guarantee a good end product. Today most brewers acknowledge that it doesn’t actually do anything, but keep up the practice as a nod to tradition.

Obviously this is just a reenactment!

Obviously this is just a reenactment!

Even if you understand that liquid can’t have feelings, some people swear by the results. There’s an entire thread on a homebrewing forum where users try to approach it scientifically, using combinations of recipes, books and reading length to try and detect differences. I’m skeptical that they were caused by anything other than random variation in fermentation temperature, etc, but I like that people are finding creative ways to explore the issue.

I had always assumed slapgan was a German word, like “vorlauf” and “lauter”. It appears slapgan is actually a bastardization of the Dutch word slapengaan, meaning “bedtime”, as in verhaaltje voor het slapengaan, “bedtime story”. So, any brewers using Goodnight Moon during slapgen, consider yourself poetic.

When I homebrewed I would mostly just pick up whatever I was reading at the time. I’ll be honest, one of my homebrewed beers got Twilight during slapgan. Sometimes I do try to match the book to the beer. My favorite example of that was probably when I read Samuel Pepys’ diary to an Old Ale I made.

So, there you go: an antiquated but fun tradition that you probably didn’t even know about unless you’ve made beer yourself. What did you read during slapgan for your favorite beer?