Two series of tests were carried out as a result of this experience:
- Extraction of the water and subsequent titration of an aliquot.
- Titration in boiling methanol.
An additional series of dry loss at 130°C has shown that a certain part of water does not release even after 20 hours. Titration of the remaining dried coffee resulted in a water content of still 0.4%.
Roasted coffee releases the water only incompletely using loss of drying or the direct KF-determination in methanol. Long-term extraction at elevated temperature helps completing water extraction. Nevertheless, KF titration in boiling methanol gives the best extraction and most reliable results.
Download the full Laboratory Report for Ground Coffee (L 061 + L 062) here
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