Every time you brew coffee, you are conducting a selective chemical extraction. Hot water dissolves soluble compounds from ground coffee particles, carrying them into your cup as the flavors, aromas, and textures you experience. But not everything in the coffee is soluble, and not everything that is soluble is desirable. The percentage of the ground coffee’s mass that ends up dissolved in the brew — the extraction yield — is one of the most important metrics in coffee science, providing a precise numerical framework for understanding why some cups taste balanced and complex while others taste hollow, harsh, or unpleasantly bitter. Understanding extraction yield transforms brewing from guesswork into a practice guided by measurable outcomes.
What Extraction Yield Means
Extraction yield is expressed as a percentage: the mass of dissolved coffee solids in the brew divided by the mass of dry ground coffee used, multiplied by one hundred. If you brew with twenty grams of coffee and your brew contains four grams of dissolved coffee solids, your extraction yield is twenty percent.
Roasted coffee is approximately thirty percent soluble by mass — meaning that roughly thirty percent of the dry weight of ground coffee can theoretically be dissolved by water under brewing conditions. The remaining seventy percent is insoluble cellulose, fiber, and structural material that stays in the filter or press as spent grounds. However, dissolving the full thirty percent produces an undrinkable brew — the compounds that dissolve last are overwhelmingly bitter, astringent, and unpleasant. The art and science of brewing lies in dissolving the right proportion of the available solubles.
The Optimal Range
The Specialty Coffee Association has established a target extraction yield range of eighteen to twenty-two percent for brewed coffee. This range represents the zone in which the desirable flavor compounds — sugars, fruit acids, Maillard reaction products, and pleasant aromatics — are fully dissolved while the less desirable compounds — harsh bitter substances, astringent tannins, and dry woody flavors — remain largely in the grounds.
Under-Extraction
An extraction yield below eighteen percent indicates that the water has not dissolved enough of the coffee’s soluble material. Under-extracted coffee tastes sour, thin, and undeveloped. The bright organic acids that dissolve first are present, but the sugars and heavier compounds that provide sweetness, body, and balance have not yet been extracted in sufficient quantity. The result is a cup that feels incomplete — sharp without sweetness, bright without depth. Under-extraction can be caused by water that is too cool, grind that is too coarse, contact time that is too short, or insufficient agitation during brewing.
Over-Extraction
An extraction yield above twenty-two percent means that the water has dissolved beyond the desirable range, pulling out bitter, astringent, and woody compounds that overwhelm the pleasant flavors extracted earlier. Over-extracted coffee tastes harsh, dry, and unpleasantly bitter — the kind of bitterness that coats the tongue and persists unpleasantly in the aftertaste. Over-extraction results from water that is too hot, grind that is too fine, contact time that is too long, or excessive agitation that accelerates dissolution beyond the optimal window.
The Sweet Spot
Within the eighteen-to-twenty-two percent range, the specific extraction yield that tastes best depends on the coffee, the roast level, and personal preference. Lighter roasts, with their denser structure and higher concentration of organic acids, often benefit from extractions toward the upper end of the range — twenty to twenty-two percent — where sufficient sweetness has been developed to balance the inherent brightness. Darker roasts, whose cellular structure has been more extensively broken down during roasting, may taste best at the lower end — eighteen to twenty percent — where the increased solubility of darker-roasted coffee does not lead to excessive bitterness. This interplay between roast profile and extraction is connected to the foundational principles explored in our article on the science behind extraction time in coffee brewing.
Measuring Extraction Yield
The Refractometer Method
Extraction yield is measured indirectly using a refractometer — an optical instrument that measures the concentration of dissolved solids in a liquid sample. A coffee refractometer reads total dissolved solids as a percentage, typically expressed in degrees Brix or as a TDS percentage. By combining this TDS reading with the brew weight and the dose weight, extraction yield can be calculated using a simple formula: extraction yield equals brew weight multiplied by TDS, divided by dose weight.
Digital refractometers designed for coffee — the most common being the VST series — provide rapid, accurate readings that take seconds to perform. This accessibility has brought extraction yield measurement out of the laboratory and into the daily practice of baristas, roasters, and home brewers. However, the measurement requires attention to technique: the sample must be thoroughly mixed, cooled to the appropriate temperature, and applied to a clean lens for accurate results.
Practical Estimation Without Equipment
Not every brewer owns a refractometer. Fortunately, the sensory indicators of extraction level are reliable once you learn to recognize them. If a brew tastes sour, sharp, and thin, it is likely under-extracted. If it tastes harsh, bitter, and dry, it is likely over-extracted. If it tastes balanced — with perceivable sweetness supporting bright acidity and a clean finish — it is likely within the optimal range. These sensory assessments are subjective, but they correlate well with measured extraction yields once a brewer has calibrated their palate through comparative tasting.
Variables That Control Extraction Yield
Grind Size
Finer grinds expose more surface area to water, increasing the rate and total extent of extraction. Coarser grinds reduce surface area, slowing extraction and lowering yield. Grind size is the most commonly adjusted variable for controlling extraction yield, and its effects are immediate and significant. A small change in grind setting — one or two clicks on a typical burr grinder — can shift extraction yield by one to two percentage points. The comprehensive relationship between grind size and brewing outcomes is detailed in our guide to why grind size matters for every brewing method.
Water Temperature
Higher temperatures increase the kinetic energy of water molecules, accelerating their ability to dissolve soluble compounds. Within the standard brewing range of 90 to 96 degrees Celsius, a shift of two to three degrees can meaningfully affect extraction yield. Water below 90 degrees tends to under-extract, producing sour, underdeveloped cups. Water above 96 degrees can push extraction into harsh, bitter territory with lighter roasts. The stability of temperature throughout the brew is as important as the starting point — a consideration examined in our article on temperature stability and its effect on brewing consistency.
Contact Time
The longer water remains in contact with ground coffee, the more material it dissolves. In immersion methods like French press, contact time is controlled directly by the brewer. In percolation methods like pour-over, contact time is determined by the interaction of grind size, dose, and pour technique with the filter’s drainage rate. Extending contact time increases yield; shortening it reduces yield. However, contact time does not act independently — its effects are mediated by grind size, temperature, and agitation.
Brew Ratio
The ratio of coffee to water affects extraction because it determines the concentration gradient that drives dissolution. A higher ratio of water to coffee — a weaker brew ratio — provides more solvent to dissolve material from the same dose, potentially increasing extraction yield. A stronger ratio provides less solvent per gram of coffee, which may limit extraction but concentrates the dissolved material in a smaller volume. Brew ratio and extraction yield are related but distinct: a brew can have a high extraction yield but a low concentration if a large volume of water was used, or a low extraction yield but a high concentration if very little water was used.
Extraction Yield Across Brewing Methods
Different brewing methods operate at different typical extraction yields, reflecting their mechanical characteristics. Espresso, with its high pressure, fine grind, and short contact time, typically achieves extraction yields of eighteen to twenty-two percent with a very high concentration. Pour-over methods, with their medium grind and gravity-driven flow, target similar yields at much lower concentration. French press, with its coarse grind and full immersion, often falls at the lower end of the optimal range unless contact time is extended.
Beyond the Number
Extraction yield is a powerful diagnostic tool, but it is not the only measure of brewing quality. Two brews at identical extraction yields can taste very different if the distribution of extracted compounds differs — a phenomenon called extraction uniformity. Uneven extraction, caused by channeling, inconsistent grind size, or poor water distribution, produces a brew in which some particles are over-extracted while others are under-extracted. The average extraction yield may fall within the optimal range, but the cup tastes muddled and unbalanced because it contains both the sour compounds of under-extraction and the bitter compounds of over-extraction simultaneously.
Conclusion
Extraction yield provides a precise, measurable framework for understanding what is happening inside your brewer. It connects the variables you control — grind, temperature, time, ratio — to the sensory outcomes you experience in the cup. Whether measured with a refractometer or assessed through attentive tasting, extraction yield is the conceptual bridge between brewing science and everyday practice. For any brewer seeking consistency, improvement, and a deeper understanding of why coffee tastes the way it does, extraction yield is not an optional metric. It is the metric that makes all other adjustments meaningful.
Daniel Almeida is a member of the editorial team at Saiba Money, where he contributes to the research, writing, and review of educational content focused on coffee culture, production, and brewing methods.
He works collaboratively to ensure that all published articles are accurate, clearly structured, and accessible to a broad audience. His interests include agricultural development, global coffee markets, and the science behind brewing techniques.
Daniel is committed to delivering reliable, well-researched information that helps readers better understand coffee from origin to preparation.