الملخص
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The extracted mass can be segregated into thirds: bitter, sour, and sweet.
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Fermentation plays a large part in the production of the sour/acidic elements in green coffee.
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We can calculate the extracted mass with dehydration ovens or refractometers.
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The coffee industry uses refractometers because they’re cheaper and they give instant readings.
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Extraction yield measurements are averages — we calculate them to see how the measurements change in response to our roasting and brewing decisions, e.g. changes in grind or temperature.
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The extremely complex chemical makeup of coffee creates complexities in refractometry that can be resolved with temperature correction calibrations.
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This process involves taking a highly accurate dehydration sample and then comparing this sample to RI readings taken at a range of temperatures. This process makes the coffee refractometer accurate to within +- 0.02%TDS.
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We emphasise the importance of pairing your sensory skills with refractometry.
New Terms
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Acidity: the level of perceived sourness and/or fruitiness.
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Agronomist: an expert in the scientific study of soil and plant management.
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Aliphatic Acids: the acids of non-aromatic hydrocarbons. In coffee, they are created through the break down of sucrose, fructose and glucose. Of these, the principal in coffee is acetic acid (vinegar).
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Caramelisation: a type of non-enzymatic browning of sugar that is brought about by thermal decomposition.
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Degradation
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Disaccharides: aka a double sugar, are a class of sugars formed when two monosaccharides are bonded by glycosidic linkage (a type of covalent bond specific to carbohydrates) Sucrose is a disaccharide.
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Dispersion (optics): when different colours of light refract at different angles —