Specific gravity

Busy day today, with a visitor learning about brewing. Here The Brewer is instructing on specific gravity reading through refractometer (indicates alcohol by volume). This is not my province, of course, but entertaining and feeding brewers is.. It was a lovely day: mild, windless and sunny, and the company was great. Alas my photographic creativity was not to the fore, but that was not the prime motivation today. I did do ironing and mending :)