Recap
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The coffee refractometer needs to be cleaned and calibrated regularly.
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Samples must be managed in a way that prevents water evaporating but also allows them to cool to room temperature when reading will be more accurate.
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CO2 content is expected to be higher in dark roast coffees, while H2O content is expected to be lower in dark roast coffees.
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The effect of these two presences in roasted coffee is to increase extraction yield values.
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Scientific literature reports a 1.3-2.3% H2O content in low temperature, slow roasts (specialty).
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When calculating extraction yield, the mass extracted from the coffee grinds will reduce the liquid retained.
New Words
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Cellulose Matrix: the honeycomb-like arrangement of cellulose cell walls which in roasted coffee grinds is ripped open and made microporous. Cellulose is a polymer made of repeating glucose molecules attached end to end.
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Deionised Water: pure water containing no minerals or suspended solids.
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Physicochemical: pertains to the physics and chemistry of something.
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Quenching: the practice of spritzing roasted coffee with water in order to speed up the cooling process.
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Solenoid Valve: an electronically triggered filling valve, combining a sprung loaded rubber seal and a magnet to trigger the movement of water through plumbing — used in espresso and filter coffee equipment.
Links From the Text
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Notes on Precision and Measurement Protocol, VST Webshop
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Syringe Filter Use and Safety Instructions, VST Webshop
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Coffee and VST Refractometers, VST Webshop
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Isopropyl alcohol, Wikipedia
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Coffee Tools App.,
