What to Actually Write in Your Brew Log (And Why Most Brewers Track the Wrong Things)

A stack of 47 brew logs from someone's first three years of homebrewing can be almost entirely useless. Every single one records original gravity, final gravity, boil time, and hop additions down to the tenth of a gram. Not one records what the beer actually tasted like, what to change next time, or why batch 23 was amazing and batch 24 was mediocre despite using the same recipe.

That's tracking data like a scientist and learning like a goldfish. If that sounds familiar, here's how to skip the frustration.

The Problem With Most Brew Logs

The default brew log, whether it is a paper notebook, a spreadsheet, or an app like Brewfather, focuses almost entirely on measurable inputs. Grain bill. Hop schedule. Mash temperature. Water volume. Gravity readings. These things matter, but they are the easy part to record. The hard part, and the part that actually helps you improve, is the subjective stuff that most people skip.

What You Should Actually Track

Here is the information that actually helps improve your brewing, organized by when you record it:

Before Brew Day

• The goal. Write one sentence about what you are trying to achieve. "Brew a drier version of last month's porter" is infinitely more useful than just recording a recipe. This gives you context when you taste the finished beer
• What changed from last time. If this is a repeat or iteration of a previous recipe, note specifically what you changed and why. "Mashed 2 degrees lower for more attenuation" or "Swapped Cascade for Centennial to test flavor difference"

During Brew Day

• Mash pH (actual, not target). This matters more than mash temperature for consistency, and most people skip it
• Any deviations from plan. Forgot to add the 15-minute hop addition? Mash ran 20 minutes long because you got distracted? Write it down. These "mistakes" are often the explanation for unexpected results
• Pre-boil gravity and volume. This tells you about your mash efficiency and helps you hit targets consistently. More useful than post-boil OG alone
• Yeast details that matter. Not just the strain, but the age of the package, whether you made a starter, and the approximate cell count. An old pack pitched without a starter is a completely different fermentation than a fresh pack with a 2L starter

During Fermentation

• Actual fermentation temperature. Not your controller setpoint, the actual temperature of the beer. Stick-on thermometers on the fermenter or a thermowell probe give you the real number. Fermentation generates heat, so the beer is often 3-5°F warmer than ambient
• Fermentation activity observations. When did vigorous fermentation start? When did it slow down? Did the airlock ever stop and restart? This timeline helps you spot problems like stuck fermentation early

At Packaging

• Final gravity and calculated ABV. The basics, but important
• Tasting notes of the flat, warm beer. This is the most underrated entry in any brew log. Taste the beer at packaging and write down your honest impression. Is it where you expected? Is there an off-flavor? Is it surprisingly good? These notes, compared against the finished carbonated beer, teach you what changes during conditioning

After Drinking

• Honest tasting notes at 1 week, 2 weeks, and 4 weeks post-packaging. Beer changes. A lot. What tasted harsh at 1 week might be wonderful at 4 weeks. Or what tasted great at 2 weeks might develop oxidation at 6 weeks. Track the evolution
• Other people's reactions. Your palate adjusts to your own beer. Ask a friend or homebrew club member to taste it and record their feedback without biasing them first
• Would you brew this again? Simple yes or no, with notes on what you would change. This single question forces you to evaluate the entire process and is the foundation for your next batch

A Template That Actually Works

Here is a template that covers it. It fits on one page and captures everything useful:

BREW LOG, [Beer Name], [Date]

Goal: ____________________

Changed from last version: ____________________

Recipe: [link to Brewfather/BeerSmith/etc]

BREW DAY

Mash pH: ___ | Pre-boil SG: ___ | Pre-boil vol: ___

OG: ___ | Volume into fermenter: ___

Yeast: ___ | Starter: Y/N | Cell count est: ___

Deviations from plan: ____________________

FERMENTATION

Temp (actual): ___ | Active by: ___ hrs

Notes: ____________________

PACKAGING (day ___)

FG: ___ | ABV: ___ | Method: keg / bottle

Flat taste: ____________________

FINISHED BEER

Week 1: ____________________

Week 2: ____________________

Week 4: ____________________

Others' feedback: ____________________

Brew again? Y/N Changes: ____________________