2911Views8Replies

Author Options:

Apparently no direct relationship between Brix and water content??? Answered

Could anyone explain to me why there is not a direct relation between the Brix scale and the water contents scale on my honey refractometer? At the low end of the Brix scale (60-70), the match is perfect, but not at higher Brix. I suspect this has something to do with the fact that there is a non-linear relationship between sugar concentration and density. It would, however, be very nice to know the proper theoretical background... :-)

Any help will be greatly appreciated, as I have been unable to find any information at all on the web. Thanks! 

Best regards,
tome

Comments

The forums are retiring in 2021 and are now closed for new topics and comments.
0
tome
tome

Answer 11 years ago

Thank you for your replies!

The information I have is all based on w/w, not w/v, but nevertheless...

I plotted SG information taken from the Merck Index against sugar contents, and estimated the Brix value based on a formula taken from Wikipedia. The results (see the two included images) corresponds well with the scale on my refractometer. The differences that are there, may well be due to a w/w vs w/v mismatch.

So.--- As far as I can tell there really is a small non-linearity in the correlation. Sugar chemistry is more complex than I can handle (being only a biologist....)..

Any suggestions?

Best regards,
tome

Brix estimation 1.pngBrix estimation 2.png
0
lemonie
lemonie

Answer 11 years ago

Yes w/w against w/v are two different things.
Sugar chemistry is a field of science in it's self, but this is just physics really. You see the non-linearality at one end of the scale, but now you've got this nice data - have you answered your question?

In w/v you've got a shift from sugars mostly bonding to water, towards sugars bonding with sugars and some water in between, the volume per unit weight changes. Or 1 litre of water doesn't weigh the same as than a sugar-crystal 10x10x10cm.

L

0
tome
tome

Answer 11 years ago

I am well aware that w/w and w/v are two different things. I see no reason, however, why one should not be linear if the other is.

These data (along with the scales on the reticle of my new refractometer) were the reason I began to wonder in the first place, so I'm afraid I have not answered my own question....

I know from making histological fixatives that there is not a good coorelation between molarity and osmolarity for sugars (making determination of tonicity more empirical than theoretical). I assume this is related to the non-linear SG correlation, and that both have to do with hydration patterns in some way or another.

I really can't explain _why_ there is no linearity. I'm still a "fresh" beekeeper, but a fellow beekeeper tells me that everybody assumes that water contents is equal to 100-Brix. If there is no linearity, that assumption can not be correct.  I have a strong dislike to things I don't understand, so even though the error is likely to be small, I would very much like to know what exactly is going on.....

Best regards,
tome

0
lemonie
lemonie

Answer 11 years ago

The w/w w/v was something I thought you knew, just a re-iteration. I've done my best at an explanation - we know as well as each other here I think.

L

0
tome
tome

Answer 11 years ago

Thank you for ideas and discussion!

I think it may be time to call one of my old professors....

Have a fine day!

Best regards,
tome

0
lemonie
lemonie

Answer 11 years ago

Fine evening (I am thanks) - I'm most likely in a different time-zone...

You too.

L

0
lemonie
lemonie

11 years ago

Oh hang on, water content. As you add sugar, the proportion of sugar increases, so 100% sugar - no water. Hmm, I can't explain this, but I can imagine / see a non-linearity in it.

L