Tool · brew log

Coffee brew log template

A brew log turns “that cup was great” into numbers you can repeat. Print the blank sheet below, or keep the log in this page: it works out the ratio and extraction yield for you, saves entries only in this browser, and exports them as a CSV file.

Updated 2026-11-02 · sources listed at the end

Where your entries are kept

• What is stored: only the entries you save, as one block of text under the name pourxlab-brewlog-v1 in this browser’s local storage for pourxlab.com. Nothing you type is sent to pourxlab.com or anyone else; the page has no analytics or trackers, and the CSV file is built inside your browser.
• How long: local storage belongs to one site in one browser and has no expiry date, according to MDN’s reference. Another browser, another device or a different profile will not see your log, so export a CSV if you want a copy elsewhere.
• Private windows: MDN notes that local storage from a private or incognito session is cleared when the last private tab closes.
• How to clear it: press Delete all entries, delete single rows with their × button, or clear the site data for pourxlab.com in your browser settings.
• If saving is blocked: browsers can refuse storage, for example when cookies or site data are blocked. The log still works, but entries last only until you leave or reload the page; the note under the buttons says which mode you are in. Export before you close the tab.

What each column means

Weigh in grams on a coffee scale — ideally one you have checked against a known weight. Fill in what you measured and leave the rest blank; only dose and water are required.

The two formulas

SCA 310 defines brew ratio as coffee per kilogram of water; the log shows the same thing inverted, as grams of water per gram of coffee, because that is how most recipes on this site are written. 320 g of water on 20 g of coffee is 1 : 16.

Extraction yield comes from two definitions in UC Davis research: TDS is the mass fraction of dissolved solids in the drink, and extraction yield is the mass that dissolved per mass of dry grounds. TDS × beverage weight gives the grams dissolved; dividing by the dose gives the yield. Example: 20 g of coffee, 320 g of beverage at 1.30% TDS is 20.8%. Wikipedia puts the same relationship the other way round: strength is the product of brew ratio and extraction.

This is the percolation formula for pour-over, drip and espresso. For French press and other full-immersion brews, the UC Davis model uses TDS ÷ (1 − TDS) × water ÷ dose instead, because the liquid held in the grounds is as strong as the cup; the extraction yield calculator has both. The log uses the percolation formula for every entry, so note immersion brews in the method column and read their EY accordingly.

Using the log to dial in

1. Brew a baseline at a fixed ratio and write everything down.
2. Taste first, then look at the numbers. Fast and sour, or slow and bitter, points at grind; see the routine on the grind size chart.
3. Change one thing per brew. The UC Davis Coffee Center’s advice is to weigh coffee and water to check the ratio, then adjust grind size and brew time toward the flavors you want. A log line per change shows which move helped.
4. Use the same words. SCA’s Flavor Wheel guide suggests starting with broad terms at the center of the wheel and moving outward to specific ones; the wheel is based on the World Coffee Research Sensory Lexicon, and the guide recommends its shared terms so tasters can communicate clearly.
5. Measure the same way. If you log TDS, follow one sampling routine; the UC Davis drip study read one drop of cooled coffee on a digital refractometer.

Printable blank log

Print blank log prints only this sheet: landscape, 12 empty rows, with the two formulas underneath. Print my entries prints your saved entries in the same columns instead.