Caffeine.supply

Half-Caff Calculator

Blend regular and decaf to dial in your caffeine. Enter your total dose and the share of regular coffee to see the grams of each and a rough estimate of the caffeine in the cup.

–
grams of regular coffee
–grams of decaf
–mg caffeine per cup (est.)
–suggested water (1:16)
–% regular
Estimate only: assumes about 6.8 mg caffeine per gram of regular and 0.2 mg per gram of decaf in the cup. Beans and brew method vary.

Regular and Decaf Grams by Dose

DoseQuarter-caffHalf-caffThree-quarter
10 g total 2.5 g regular + 7.5 g decaf 5.0 g regular + 5.0 g decaf 7.5 g regular + 2.5 g decaf
15 g total 3.8 g regular + 11.3 g decaf 7.5 g regular + 7.5 g decaf 11.3 g regular + 3.8 g decaf
20 g total 5.0 g regular + 15.0 g decaf 10.0 g regular + 10.0 g decaf 15.0 g regular + 5.0 g decaf
30 g total 7.5 g regular + 22.5 g decaf 15.0 g regular + 15.0 g decaf 22.5 g regular + 7.5 g decaf
40 g total 10.0 g regular + 30.0 g decaf 20.0 g regular + 20.0 g decaf 30.0 g regular + 10.0 g decaf
60 g total 15.0 g regular + 45.0 g decaf 30.0 g regular + 30.0 g decaf 45.0 g regular + 15.0 g decaf

Regular grams = total dose x the regular share; the rest is decaf.

Frequently Asked Questions

What is half-caff coffee?
Half-caff is a blend of equal parts regular and decaf coffee, so a cup has roughly half the caffeine of a fully caffeinated one. You can buy pre-blended bags, but mixing your own beans lets you choose any ratio.
How much caffeine is in half-caff coffee?
A cup made with half regular and half decaf lands near half the caffeine of a regular cup, so roughly 45 to 50 mg per 8 fl oz instead of about 95 mg. Decaf still holds a few milligrams, and real numbers vary with the beans and brew method.
How do I make half-caff at home?
Weigh your total dose, then weigh half as regular beans and half as decaf. Grind them together or separately, then brew as usual. For a 20 g dose that is 10 g regular and 10 g decaf.
Should I mix beans before or after grinding?
Either works. Mixing whole beans first is quickest, but regular and decaf can differ in density and roast, so for the most even extraction grind each on its own and combine the grounds.
Where do I find good decaf to blend?
Pick a decaf that roasts to a similar level as your regular coffee. Browse our 619 specialty coffees, then use the caffeine calculator to check your daily total.

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