Coffee Extraction Calculator

In short Extraction yield is the share of the dry coffee that actually dissolved into the cup, and it is the number that separates good coffee from strong coffee. The whole of it fits on one line: EXTRACTION EQUALS TDS TIMES THE BEVERAGE RATIO. Take 20 g of coffee and 320 g of water, and the grounds keep about twice their own weight, so roughly 280 g reaches the cup — a beverage ratio of 14. If a refractometer reads 1.35% TDS, the extraction is 1.35 x 14 = 18.9%, meaning 3.78 g of the 20 g dissolved. Everything on the right of that equation is a ratio, which is why doubling the coffee and the water together changes neither the strength nor the extraction, and why recipes are quoted as 1:16 rather than in grams. STRENGTH AND EXTRACTION ARE NOT THE SAME THING and confusing them is the most common mistake in brewing. Strength is solids per gram of liquid — how it tastes in the mouth. Extraction is solids per gram of coffee — how much you got out of the beans. A weak cup can be over-extracted and a strong one badly under-extracted, and only the ratio connects the two. If a brew tastes thin and sour you need more extraction, which means a finer grind or a longer contact time; if it tastes thin and dull you may simply need more coffee. The conventional target is 18 to 22% extraction at 1.15 to 1.35% TDS, which comes from a consumer panel in the 1950s rather than from any law of nature — plenty of excellent coffee sits outside it and modern equipment reaches higher extractions cleanly. Two honest limits. The retention figure is the only guess on this page, so if you weigh what actually lands in the cup and enter that instead, nothing here is estimated at all. And a refractometer reading is only as good as its calibration, its temperature and its filtering: two decimals on the screen do not mean two decimals of truth.