BH – In your book Dear Coffee Buyer, you mention an additional flotation step that can help distinguish great coffees. We understand that this process involves agitating the cherry instead of simply decanting the floaters from a static water tank. How do farmers establish a dividing line between the cherry they want to keep and the rejects? (Does it tend to involve a repass?)
RB – On the whole, they are following the guidelines they’ve been handed or have found. Coffee farming is like anything else. There are a handful of people who are actively testing the boundaries, experimenting outside conventions, and there are the people who do what their neighbor or the national coffee agronomy org tells them is the right thing to do. As with anything else, mixed results on both sides, right?
BH – Is flotation a step producers use only for their very-high-scoring lots, or do they tend to do this with all their coffee?
RB – There are no absolutes here, of course. If they use it, they’ll usually use it across the board. Keep in mind, all coffee gets sold. They’re not removing the bad cherries, they’re separating them. They get processed and sold separately. Everything gets sold.
BH – You mention that whilst it is important to avoid water wastage and contamination from processing, it is important to use only fresh, clean water in fermentation and washing. Can you elaborate on this for us? (What are the risks involved with using recycled water?)
RB – I’m conscious of the incredible water expenditure involved in top-quality washed coffees. However, it’s risky to use recycled water in any part of the process that directly touches the mucilage. Prior to pulping, the cherry skin protects the seed from potential adverse effects of recycled water. Without that protective skin, you’re running the risk of fermenty water + mucilage negatively affecting cup quality.
BH – Have you found any correlation between bean quality and the use of water in fermentations?