hist-brewing: mash temperature control/ reflection off the water

Martyn Cornell mcornell at blueyonder.co.uk
Thu Mar 4 15:43:17 PST 2010

On 04/03/2010 20:25, "Deborah Wood" <garwood2 at sympatico.ca> wrote:

> The surface tension of the water changes as it is heated,

I believe (but I'm prepared to be corrected) that it's the refractive index
of the water that changes as it reaches the right temperature, and "when you
can see your face in the water" was, indeed, the method used by
pre-thermometer brewers to gauge when the right temperature had been
reached. (This is frequently misinterpreted today by commentators on old
brewing texts as being something to do with when the steam had cleared from
the water.)

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