Brix vs % Residual Sugar

[CiderSupply.com]

Hi Group - does anyone have a resource, chart, or way to convert Brix values to Percent residual sugar for Ebulliometer use? 

I need to dilute a sweet cider down to 2% residual sugar, and i believe that diluting cider down to 2 Brix is nothing close to what 2% residual sugar really is. As a result my ebulliometer alcohol calculations will be way-off.

I'm also thinking about getting one of these test kits but not sure if they are junk: 

https://www.piwine.com/clinitest-residual-sugar-test-kit.html#343

Any help to demystify would be great!

Best regards

Chris Rylands

[gareth chapman]

Brix as a scale corresponds directly to the amount of sugar, however how you measure it is the issue, both refractometers(no use for fermented product) and hydrometers are affected by other substances in the cider. I would say that a hydrometer reading, even accounting for other substances affecting the reading would be infinitely more accurate than the test kit.

[Claude Jolicoeur]

Chris, if you want to evaluate the amount of residual sugar in your cider, I think the best way is to take a sample of the cider, add yeast and nutrients and ferment to dryness in warm location. Then difference between SGs of the 2 ciders would be related to the amount of residual sugar.

Claude

[Andrew Lea]

Actually the Clinitest / Benedict reagent test can be surprisingly accurate to estimate  low levels of sugar by small scale wine or cider makers. The chemistry is traditional and well known see eg here http://seniorchem.com/6.%20Reducing-Sugars2.pdf. It has been discussed here several times before if you search the archives. 

 It’s been in use for probably a century or so and is much cheaper than the alternative of sending it out to a lab for eg HPLC. One of its advantages is that it tests almost specifically for reducing sugars (i.e. glucose and fructose) and is not affected by other things that affect low SG readings such as glycerol and sorbitol. If you make up sugar standard solutions that will improve the accuracy. 

But Claude’s suggestion of a forced fermentation and measurement of SG difference is probably equally as good. 

Andrew

Wittenham Hill Cider Portal
www.cider.org.uk

On 15 Feb 2021, at 16:51, gareth chapman <chappe...@gmail.com> wrote:

Brix as a scale corresponds directly to the amount of sugar, however how you measure it is the issue, both refractometers(no use for fermented product) and hydrometers are affected by other substances in the cider. I would say that a hydrometer reading, even accounting for other substances affecting the reading would be infinitely more accurate than the test kit.

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[Claude Jolicoeur]

Le lundi 15 février 2021 à 15:21:49 UTC-5, Andrew Lea a écrit :

But Claude’s suggestion of a forced fermentation and measurement of SG difference is probably equally as good. 

But it will take more time before you get a result...

[Miguel Pereda]

I think the concept of dry cider needs to be considered. Ciders with a density of 1000 can still have 4 grams/L of residual fructose. I would suggest FTIR analysis is faster and cheaper than HPLC.

Miguel Ángel Pereda.

[Bartek Knapek]

 To get a feeling for the amount of sugar, you can use following approximation.

- 0.001 SG corresponds to 2.1g/l sugar +/- 10%
- the decrease is constant and even, all the way down to the final SG reading

- 2% sugar = 20g/l (assuming w/v, but w/w is also close)

so
- 2% sugar is ~0.010 SG above a final gravity of a dry cider
- 0.010 SG corresponds to ~2.5 Brix

The final gravity can be anywhere between 0.995 - 1.005.
If you cannot ferment a sample to complete dryness for test, then you should assume 0.995+0.010=1.005 as a safe dillution target.

But the accuracy of ebulliometer for a low-alcohol reading is quite poor (little delta in temp -> large delta in %vol).
And you will additionally need to multiply the result due to dillution, increasing the error further.

Perhaps the boiling method + Tabarié equation would be a better option for a sweet cider.

// Bartek

W dniu 15.02.2021 o 07:46, CiderSupply.com pisze:

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[CiderSupply.com]

Thank you all for the insight and clarification. I think i will try and use the Clinitest to know how far to reduce residual sugar down to 2% residual so i can keep using my DuJardin-Salleron ebullometer for my sweeter small-batch cider experiments. My mistake was not to keep track of initial and final SG and back sweetening before trying to use the ebullometer.

Thanks again

Chris Rylands