Carbohydrates in wine – residual sugar, and why nearly all online guides are wrong

I’ll come back to this subject in more detail later, for now here’s me trying to help out folk on r/keto as to why wine is very low carb, and not fairly high per glass as listed everywhere online:

–> http://www.reddit.com/r/ketogains/comments/2cypq9/consuming_red_wine/cjkgsbb

darthluiggi
If I recall correctly, macros and calories in wine are calculated by averaging various and different batches together, so carbs may be a little lower than stated.

More info here: http://www.reddit.com/r/keto/comments/1g8tu0/

Depending on types of wine, a glass may be 3-5g.

Ash Simmonds
WTF kind of jailbait summer breeze swill are people drinking?

Dry red wine has 2-10g of residual sugar PER LITRE, not glass. On a weight comparison that’s 10x less carbs than your average commercial bacon.

You would need to drink several bottles for it to be an issue with keto carb-wise, but alcohol DEEPENS ketosis, hence “alcoholic ketoacidosis”.

Of course it does a bunch of other stuff that’s not ideal, but in the end non-sweet wine shouldn’t be a consideration keto-wise any more than Diet Coke.

LoCHiF
The USDA disagrees:

http://ndb.nal.usda.gov/ndb/foods/show/4226?fg=&man=&lfacet=&format=&count=&max=25&offset=&sort=&qlookup=red+wine
http://ndb.nal.usda.gov/ndb/foods/show/4418?fg=&man=&lfacet=&format=&count=&max=25&offset=&sort=&qlookup=red+wine

and so on.

You may notice that the majority of the carbs aren’t sugar.

Ash Simmonds
Yep, and you may notice they don’t actually flat out say “carbohydrates”, they say “carbohydrates, by difference”.

– http://www.ars.usda.gov/Main/docs.htm?docid=6233&pf=1&cg_id=0#CHO

How is Carbohydrate, by difference determined?

Carbohydrate is determined as the difference between 100 and the sum of the percentages of water, protein, total lipid (fat), ash, and, when present, alcohol. Total carbohydrate values include total dietary fiber.

Total carbohydrate by difference = 100 – [water, protein, total lipid, ash and alcohol in g/100g]

It’s really confusing, I know – I’ve spent years trying to figger this out and I’m still going batshit crazy trying to sort it out, unfortunately there’s nothing online that really tells the full story, and everything else that has been written is based off of bad source information so you see how the whole carbs/wine thing is wrong. Guess I’ll have to write the definitive guide myself when I get a chance.

Basically, carbs aren’t MEASURED in wine because it’s very difficult to do, they’re CALCULATED (guessed, really), that “by difference” thing means they don’t really know *what else* is in the wine, so they just assume it’s carbohydrates. But AFAIK there is no form of carbohydrate in wine that is not sugar, which can only be so-called “residual sugar” (leftover from fermenting, whatever isn’t turned to alcohol) – the other stuff is known as “carbohydrate equivalents” which to be honest are still really oddball for determining this stuff.

So, check this out when they actually MEASURE carbs – not specificaly residual sugar – in wine:

– http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072009000400018

– http://bashanfoundation.org/shela/shelawhitewines.pdf

Analysis of the carbohydrates of a selection of 11 different Israeli white wines of the Sauvignon Blanc type revealed five sugars: fructose, glucose, sucrose, maltose, and maltotriose. Fructose (0.2-2.0 g/liter) and glucose (0.4-0.8 g/liter) were the major components, followed by sucrose, maltose, and maltotriose. Glycerol (6.3-8.3 g/liter) was found in all samples.

Basically, the only carbohydrates in wine are sugars, so whatever you’re reading on those nutrition databases which are based on “carbohydrates, by difference” are just a best guess of *something* in the wine that isn’t alcohol or fat or protein.

Lots more to come on this subject in the future, but for now:

TL;DR – the carbs in wine are mis-reported across the board because of errors in calculations in the original source data. Don’t stress about carbs in normal “dry” table wine – you have to drink ridiculous amounts for it to matter ketogenically, in which case you have other issues to worry about