Hydrometers less useful than we thought?

Mar 18, 2010 5 Replies

We use hydrometers to gauge sugar content. Since hydrometers measure solubles solids and soluble solids are mostly sugar in wine grapes, that works pretty well. In researching raspberries, I found that sugar can make up a much smaller fraction in other fruit. A clear sample of raspberry juice might measure 9 Brix, but contain only 3 g/100g sugar. More detail here:



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If we're just talking about raspberries, that may not be a big deal. It's unusual to make wine from 100% raspberry juice - I've never done it with more than 25%. So, for the entire must, the error is a lot smaller. Might be a problem with other fruit though.



Erroll

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Since hydrometers measure

I'm using them for more than 5 years and I will never change them. They are the classic method for me and I'm completely satisfied. ;)

Ditto for the last 20+ yrs.

McK.

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Well, this is why the big winemakers send their samples to a lab with GC/MS and titration equipment. Of course, they have much more to lose if they have an "off" batch.

I guess the big deal for us hydrometer users is that non-assimilable solutes contribute to density in the same way as assimilable solutes, and the hydrometer can't tell us what the ratio is. However, it can tell us how much assimilable solute has been metabolized by the yeast, which is still a useful piece of information.

Marshall

Thank you Erroll. And Marshal you are exactly right.

just because we have been using hydrometers for "ever" doesn't mean it is the best.

Can you think of a big winemaker that makes top quality wine? Of course the sheer bulk of the wine in gallons allows for economies of scale that can justify using a gas chromatograph/mass spec. Smaller wineries will use hydrometers as an indication as to when samples should start going to the lab for enzymatic measurements of glucose/fructose.

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