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How much brew water will fill your travel mug?
Published by Ratio Kettle
Weigh how much finished coffee your current recipe delivers. Divide your target drink weight by that measured yield, then multiply the original coffee and water doses by the result. Grounds and brewer surfaces retain water, so the poured and delivered weights differ.
Choose your actual fill line
Set the empty mug on the scale and tare. Pour in water to the level you would comfortably carry below the lid. The reading gives an approximate target mass for a black coffee of that volume. If you usually add milk, decide how much of that space belongs to milk first.
A travel mug's advertised capacity may correspond to a brim-full vessel. Checking the mug you actually use avoids producing a few tablespoons you cannot pour in.
Collect one useful brew record
Make a hot filter brew that tastes right. Weigh the dry coffee and input water, then move the dripper away, tare a clean receiving vessel and weigh the drink. Suppose those values are 18 grams of coffee, 288 grams poured and 252 grams delivered. The difference between poured and delivered weight in this example is 36 grams. Your own reading can differ.
For 315 grams of black coffee, the scaling factor is 315 ÷ 252 = 1.25. Try 22.5 grams of coffee and 360 grams of water. For a 315-gram drink including 35 grams of milk, aim for 280 grams of coffee. The same record scales to 20 grams of grounds and 320 grams poured.
Weigh the second cup
Draining time, bed depth and the water left in the brewer can change as you scale up. Measure the finished batch again instead of assuming an exact result. Record just four numbers for the next morning: dry coffee, water poured, coffee delivered and milk added. If you change beans or equipment, check the yield again.