Residual Sugar Testing

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Ajmassa

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I was on Vinmetrica’s website to order som fresh reagents and saw they have a new kit available for residual sugar.

The description on the site breaks down all the ins and outs of the method used— which is specifically for “reduced” sugar. (With an extra step to test sucrose if desired) They do a great job detailing the test and explaining the science involved. $89 for the reagents and $140 for reagents with labware

“Specifications:
-Sensitivity and range: detects down to 0.5 g/L reducing sugar in a 2 mL sample; upper limit is determined by dilution (samples with more than about 25 g/L can be diluted as needed)
-Accuracy: 0.2 g/L reducing sugar”

https://vinmetrica.com/product/new-residual-reducing-sugar-assay-kit/Adjustments.JPG
 

mainshipfred

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I don't know how true or accurate this is but I was told a diabetes test kit from a pharmacy can also test residual sugar.
 

Ajmassa

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I don't know how true or accurate this is but I was told a diabetes test kit from a pharmacy can also test residual sugar.
I remember reading something about that as well. I completely forget the name. But I remember reading it was product available at pharmacies but unfortunately it’s no longer sold or possibly discontinued.

Still waiting on that handheld digital sugar meter to be invented!
Also the variable capacity carboy!

However the “laser cutter” hand tool i always envisioned is almost ready! I’ll be handing over my money when they get them powerful enough to at least cut Sheetrock. But making progress. Check it out https://torchexpro.com/pages/tactilax
 

Ajmassa

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@Ajmassa I still have some of the Clinitest tablets for residual sugar testing, I think that's what you are referring to.

https://www.labsupplyoutlaws.com/bayer-clinitest.htm
Nailed it! Thanks. Yeah there’s some old threads on here discussing it I remember now. Which is where I initially became aware.

@sour_grapes —— that’s real? I’v never seen those signs in my life. Seems incredibly random lol
“Cash for gold”, “we buy junk house”, “cash4junk”, “cash your junked cars” —sure.
“Cash for unused diabetes testing supplies” —that’s a new one for me for sure!
 

sour_grapes

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Nailed it! Thanks. Yeah there’s some old threads on here discussing it I remember now. Which is where I initially became aware.

@sour_grapes —— that’s real? I’v never seen those signs in my life. Seems incredibly random lol
“Cash for gold”, “we buy junk house”, “cash4junk”, “cash your junked cars” —sure.
“Cash for unused diabetes testing supplies” —that’s a new one for me for sure!
Sadly, it is very real. I see these signs frequently -- moreso in rougher parts of town. For a long time, I ALSO thought this ploy seemed weird and random, but I eventually caught on (with some help from the googler). Evidently, the gig is that some diabetics get or buy strips heavily subsidized by their insurance, so they pay far less than retail. They then hold back on using all of them, and then sell the extras to 3rd party vendors. The vendors in turn sell them to diabetics who lack insurance altogether; the vendors sell them at less than retail, but (obviously) above what they pay for them.

All of this is legal. Just a damn sad state of affairs.
 
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1d10t

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Decades ago there was a little shack of a store front in WVA that had a sign out front announcing they did PAP tests.
 

Ajmassa

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Oh my goodness! That was a bit uncanny!
I opened the post and happened to be right there! (Which is often) Lots of work at Temple’s Episcopal hospital at Kens. & Lehigh over the years, every holiday picking up a pound cake from Stock’s bakery, and just yesterday looked at a new job at one of those old monstrous Church’s right there on Allegheny, Nativity BVM.

I should take more notice of my surroundings! But To my credit—there’s plenty of sights and experiences in the hood distracting me !
 
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sour_grapes

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I opened the post and happened to be right there! (Which is often) Lots of work at Temple’s Episcopal hospital at Kens. & Lehigh over the years, every holiday picking up a pound cake from Stock’s bakery, and just yesterday looked at a new job at one of those old monstrous Church’s right there on Allegheny, Nativity BVM.

I should take more notice of my surroundings! ...Ya know, when I’m not dodging bullets, drug dealers and junkie beggars! To my credit—when “suicide proofing” psych units in the heart of the “Badlands” there’s plenty of sights and experiences distracting my noticing of the signs.
My sister just LOVES Stock's pound cakes. I don't have much of a sweet tooth, so I am indifferent.

Be safe!
 

jgmillr1

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I was on Vinmetrica’s website to order som fresh reagents and saw they have a new kit available for residual sugar.
Getting back to the original topic here...

As we all know, the issue with using either SG or refraction to determine the residual sugar is the alcohol confounding the measurement. What about getting rid of the alcohol? Just thinking here...

So, what if you took a 100ml sample of wine, boiled it to evaporate the alcohol, cooled and reconstituted it back to 100ml, and then finally took the SG or refractometer brix measurement? Seems like that might work, but haven't tried it myself yet.

Of course that still leaves behind the various dissolved acids which will definitely offset the measurement. So this technique may be most accurate for sweet wines and less reliable on wines under 10g/L residual sugar.
 

cmason1957

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Has anyone tried using a glucometer to test RS?
Someone asked this same question over on a Facebook post today. The answer there is more than likely the correct answer.

"I don't think this would work. Glucometers don't actually check "sugar". Plus they're calibrated to correct for the serum concentration of other minerals, etc. and Ph of serum plasma."
 

Ignoble Grape

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Someone asked this same question over on a Facebook post today. The answer there is more than likely the correct answer.

"I don't think this would work. Glucometers don't actually check "sugar". Plus they're calibrated to correct for the serum concentration of other minerals, etc. and Ph of serum plasma."
Huh. So my daughter is Type 1 - and this question is intriguing.

Step 1: see if anything even shows up on the glucose meter. They read for regular coke/soda. Which is a fun trick to make sure the waiter did, in fact, bring diet.

If you know the base RS of a given liquid, and then use the glucometer, couldn't you figure out a conversion formula? Perhaps do some comparisons with a brix meter? I have a friend who offered to loan me his brix meter. I'm going to play with this one.
 

Ignoble Grape

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Am I oversimplifying, or wouldn't you just use the Brix (converted from SG)?
No, you're right - the brix meter is the tool to use for this exercise. The question is: CAN one use the glucometer? Which may not be possible if one can't get a reading in the first place.
 
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