North American Fruit Explorers mailing list at ibiblio

[Claude Jolicoeur <cjoli@gmc.ulaval.ca>]

Derry,
We had about the same discussion in November 99... Following is a message I
sent to the list at that time. I also remember I had made a relation
between % sugar and specific density, but I don't find the message here at
the office. I will look for it at home this evening.

Written 11 Nov 1999: 
>I have used hydrometers for about 10 years now. This is an essential tool
>for anyone who want to make cider (I mean hard cider) as the sugar content
>of juice is of utmost importance - it is the sugar that transform into
alcool.
>What an hydrometer measures is the specific gravity of a liquid, in
>relation with pure water - i.e. pure water has a S.G. of 1.000 and a volume
>of apple juice will be heavier than the same volume of water. Hence a S.G.
>of 1.050 means that if you had a volume of water that weighed 1 lb, that
>same volume of your juice would would weight 1.050 lb.
>You also have the Brix reading that gives you the % of sugar. Note that
>this an approximate conversion as other constituents of apple juice may
>modify the S.G. Remember that the hydrometer only measures S.G. and,
>usually, the Brix reading is calibrated for average grape juice - so the %
>sugar content may be quite innacurate with apple juice. This is why I
>always prefer to note my readings as S.G. rather than as % sugar when I use
>the hydrometer.
>Over the years I have accumulated considerable data and comparisons of S.G.
>readings. In particular, I have noted that my homegrown Cortland apples
>(and other varieties also) always have a S.G. considerably higher than
>commercially grown apples of the same variety. To give you numbers, store
>bought Cortland normally test around 1.040 - 1.045, while mine are rather
>between 1.055 and 1.060 depending in the season, degree of ripeness when
>picked, elapsed time since picking.
>I wish you a lot of fun with your new toy.
>Claude
>

A 20:08 01.05.14 -0700, vous avez écrit :
>Claude,
>
>Those are interesting results.  I have what I think is a refractometer,
cost about
>$250, and gives results in % soluble solids.
>
>How can I relate % soluble solids to specific gravity?


 

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