[nafex] Sweetest Apple
cjoli at gmc.ulaval.ca
Tue May 15 19:11:57 EDT 2001
Earlier today, I wrote:
>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.
Here is the relation - I hope it may be helpful to some who were not member
of the list at the time. I wrote this on November 13, 1999:
>1- Relation between Brix and S.G.
>If I make a simple linear relation between these 2 scales on my hydrometer,
>I get the following relation:
>Brix (in %) = 0.557 + 236 x (D-1)
>which is accurate within + or - 0.1% between D = 1.030 and D = 1.080, D is
>the specific gravity (S.G.)
>2- Relation with refractive index measurement, and acidity
>I found in Smock and Neubert "Apples and apple products" this interesting
>Apple variety : Jonathan Winesap Delicious
>S.G. 1.057 1.060 1.064
>% S.S. 13.8 14.5 15.5
>Total sugar (%) 11.7 12.1 13.4
>Acidity (as malic, %) 0.45 0.48 0.21
>pH 3.56 3.59 4.02
>Calculated Brix (%) 14.0 14.7 15.7
>The line % S.S. is soluble solids obtained from the refractive index.
>The line "Calculated Brix" is from the abovementioned relation. We can see
>that Brix scale is very close to the % S.S. The real total sugar is a
>little more than 2% less than either Brix or S.S. number.
>As of acidity, from the table, there is no direct relationship between pH
>and titration result. We see that Delicious has higher pH and lower acid
>content - this is normal. However, between Jonathan and Winesap, we see
>more acids in winesap with a higher pH (a higher pH indicates less
>acidity), which apparently is a contradiction.
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