How to plan a brew day: the numbers you need before mash-in
A brew day goes wrong in the first twenty minutes or not at all. The strike water is the wrong temperature, or there isn't enough of it; the pre-boil volume comes up short and the gravity high, and the rest of the day is spent correcting. Every published checklist tells you to "heat strike water" and "collect pre-boil volume." None of them can tell you how much or how hot, because they don't know your kettle. Your profile does. Here is the whole day, computed for the default profile brewing 11 lb of pale malt at 72 %:
| Step | The number | Why |
|---|---|---|
| Strike water | 4.4 gal at 163 °F | for a 152 °F mash from 68 °F grain at 1.5 qt/lb |
| Sparge water | 4.4 gal at 171 °F | batch sparge; the rest of the 8.8 gal |
| Pre-boil, hot | 7.5 gal | 1.2 gal boils off in 60 min |
| Pre-boil gravity | 1.044 | the reading that tells you the mash went right |
| Post-boil, hot | 6.2 gal | shrinks 4 % cooling; kettle keeps 0.5 gal |
| Into the fermenter | 5.5 gal at 1.053 | 11 lb pale malt at 72 % |
| IBU | 39 Tinseth · 47 Rager | 1 oz 10 % at 60, 1 oz at 10 |
| Pitch | 206 billion cells | 2.1 fresh liquid packs, or one and a starter |
| Into bottles | 4.75 gal | 50 twelve-ounce bottles |
Default US profile: 5.5 gal batch, 72 % efficiency, 60-minute boil, 1.25 gal/hr boil-off, 0.5 gal kettle and fermenter losses, batch sparge at 1.5 qt/lb. Palmer's strike equation, Tinseth and Rager, Fix's pitch rates. Computed by the engine that runs the panel above.
The one reading that saves the day is the pre-boil gravity. Everything after the mash follows from it. If the sheet says 1.044 and the hydrometer says 1.040, you know before the boil starts that the mash came up short — and you can fix it while there's still a boil to fix it in: 36 more minutes on the burner, or 12 oz of DME stirred in. Find out at the OG reading instead and the only fix left is a smaller batch.
How long does an all-grain brew day take?
Four to six hours of hot side is the honest range — Learning to Homebrew's "~4–6+ hours", "~5–8" with the cleanup nobody plans for — and the profile fixes two of the blocks: the boil is your 60 minutes, and the mash is whatever the recipe says, usually 60. The rest is heating, draining and chilling, and those depend on the burner and the chiller more than anything a page can compute. What a page can do is make sure none of the hour is spent finding out what the strike temperature should have been.
| Block | Typical | What decides it |
|---|---|---|
| Heat strike water | 20–40 min | 4.4 gal from tap to 163 °F: burner power |
| Mash | 60 min | the recipe; 45 is often enough for a well-crushed base malt |
| Lauter and sparge | 20–45 min | batch sparge is quicker than fly; BIAB quicker still |
| Heat to boil | 15–30 min | 7.5 gal from ~150 °F |
| Boil | 60 min | the profile's boil length — and its 1.2 gal of boil-off |
| Chill and transfer | 15–40 min | immersion chiller and cold tap water, or an ice bath and patience |
| Clean up | 30–60 min | the block every timeline forgets |
Ranges from the sources above; the boil and volumes from the default profile.
Brew day checklist
The sheet the print button makes is this checklist with your numbers filled in and a blank beside each for what happened. Before the day: weigh and mill the grain, weigh the hops into labeled cups by minute, make the starter if the pitch line above says so, and read the profile's numbers once more. On the day, in order:
- Heat the strike water to the sheet's temperature — a couple of degrees over if the tun is cold — and add the brewing salts now, not later.
- Dough in, stir, read the mash temperature at five minutes. Write it down.
- Heat the sparge water during the mash. Vorlauf until clear, then run off and sparge to the pre-boil volume on the sheet — measure it.
- Cool a sample and read the pre-boil gravity. Compare it to the sheet. This is the moment to boil longer or add extract, not later.
- Boil for the profile's length; hops in at their minutes; kettle finings at 10.
- At flame-out, note the post-boil volume — it's your boil-off rate, measured.
- Chill, transfer, read the OG and the volume into the fermenter, pitch the cells the sheet says.
- Log the four numbers below. If the efficiency isn't the profile's, save the one you got.
The sheet is only as good as the profile, and two of the profile's numbers can't be looked up — they're yours. Boil-off depends on your kettle's width and your burner; brewhouse efficiency on your mill gap and your sparge. Every logged brew measures both. Save them and the next sheet's strike volume, pre-boil target and expected OG are computed from what your kit actually does, which is the whole point of a profile. Guess them and every sheet is wrong the same way.
What to write down, and what it tells you
Four readings and two volumes turn a brew day into a number you can act on. Pre-boil volume and gravity together give the mash efficiency — how much of the grain's sugar you got into the kettle. OG and volume into the fermenter give the brewhouse efficiency, the number the recipe calculators need: log 1.050 into 5.5 gallons from the example bill and the day ran at 68 %, not the profile's 72, and the next batch should be planned at 68 — or milled finer. Post-boil volume against pre-boil gives the boil-off rate, measured instead of assumed. And the FG, days later, gives the ABV — 1.053 to 1.012 is 5.4 % — and the attenuation, which is the yeast's report card.
On the example day the strike water is 4.4 gal at 163 °F for a 152 °F mash. Thin the mash to 2 qt/lb and the strike temperature drops to 160 °F, because there's more water to carry the grain's cold; thicken it to 1.25 and it rises to 165. That's why the sheet reads the thickness from your profile instead of printing "165 °F" the way a generic checklist does — and why a mash that lands two degrees low every time is usually a thickness that doesn't match the number you planned with.
The honest summary: nothing on this page is cleverer than the standalone calculators — it's the same engine, with the retyping removed. What it adds is order: the numbers in the sequence the day happens, on paper, with a place to write what you got. Save the brew when you're done, and the third sheet you print will know your kettle better than you do.