I think Boak & Bailey’s most recent approach to blogging of posting little and often is great. It’s what I used to do more often, and then at some point all my blog posts turned into 1000+ word articles with lots of research.

My instead, I’ll be posting about a question that recently came up on Reddit’s /r/homebrewing subreddit, namely what logs and records do people keep about their homebrewing. I left a comment there, but in addition, I also wanted to post about it here, also to explain my thoughts behind it all.

I started homebrewing in late 2012. Back then, I kept some very basic records, but I quickly noticed that these weren’t quite enough to reliably reproduce recipes. Not that I actually rebrewed many beers, but having the ability to reproduce one recipe right even when the underlying conditions change (raw materials are always variable, timing can be very different when you just wing your brew day, etc.) is something very valuable, for myself, for others to reproduce, and eventually for brewing historians. Not that I ever expect beer historians to disseminate any of my records, but you never know. Even if it’s just “leading by example” by posting this article for others to pick up similar habits. I think it was Ron Pattinson who wrote that beer history will lose a lot of knowledge simply because how bad the record-keeping in many craft breweries is, but I can’t find a source for it. But I digress…

So this is what a log of a typical brew day looks like:

I write down the date and the beer style that I intend to brew, followed by the grist. The grist is all the malts, their technical name, if known also the producer, and their weight. This would e.g. be:

• 3.3 kg Mild malt
• 0.2 kg Simpsons CaraMalt

This is then followed by a log of all the steps that briefly describe what I did, usually starting with dough-in (mash-in). All log entries are timestamped with a minute resolution. For example:

• 10:45 dough-in with 11 l water at 71°C -> 65°C; rest 60 min

That says that at 10:45 I doughed in the malt with a certain amount of water at a specific temperature, resulting in a mash temperature of 65°C, followed by resting the mash for 60 minutes. Rest lengths (“60 min”) describe intention, while the timestamps describe the actual times when an action happened. This may seem like a very technical distinction, but reflects that brew days are sometimes a bit chaotic, things go slightly wrong, you miss an alarm and only get to do something 5-10 minutes later than planned.

If there is step mashing involved, it’s usually indicated like this:

• 11:45 heat to 72°C
• 11:53 reached 72.6°C; rest 10 min

For decoction mashes, it’s more something like this:

• 10:26 draw off 8 l thick mash for decoction
• 10:32 bring decoction to boil
• 11:14 boil decoction for 5 min
• 11:20 mix back decoction
• 11:24 -> 72°C; rest 10 min

For lautering, I document the transfer to the lauter tun, when I start lautering (which is usually preceded by recirculation), and the strength of the first runnings in °Brix which I measure using a refractometer.

I also document the °Brix of the last runnings when I’ve collected enough wort. The wort boil is documented in when it starts and and when it finishes. The hop additions are all documented in their timing in minutes before the end of the boil (e.g. 60 min, 0 min, or during whirlpool at 95°C), the hop variety (e.g. Saaz, EKG, …) and the alpha acid content.

After the end of the boil, I measure the post-boil gravity using the refractometer first before I chill down the wort. Once the wort is chilled, I then measure the OG using a saccharometer in °P, e.g. 12.5°P. I document the final temperature reached when chilling, and what yeast I pitched when. Once fermentation is finished, I document the FG, also in °P, followed by the calculated %ABV. I of course also record the volume in the fermenter.

The OG actually used to be relevant in Germany until 2024, when the German government loosened the taxation requirements for homebrewers by increasing the tax-free maximum annual amount of homebrewed beer per household from 200 litres to 500 litres, and by lifting the requirement of having to report every single batch by sending an email where and when it was supposed to be brewed, and what the OG was going to be. This requirement had already been relaxed by many customs offices, but only fully became law in 2024.

So that’s how I document all my batches of beer that I brew. It may seem like overkill, but it’s been useful in the past to understand extract efficiency, to analyze issues during the brew day, and to reliably reproduce certain beers like the annual Czech Dark Lager I brew for Christmas together with my friend Ben.