Residual Sugars: How Much is There?

And even if fermentation is incomplete and there are residual sugars in the wash, they would have to pass through the distillation process to end up in the spirit. Yes?

Can that happen?

(And am I correctly following your line of thought here, @Victor?)

@MadSingleMalt, yes, you are on track with my line of thought. I don't have answers to these questions, but I would very much like to know.

I agree with your statements. You also don't need sugar to give the impression of sweetness. Here is a bit of bedtime reading for you whiskyscience.blogspot.co.nz/2016/12/…

@Victor Ralfy talks about Barley sugar, barley citrus....I tune him out when he gets too esoteric...

(but I never tune YOU out)

@Hewie - Thanks for the link!

@Victor - despite some Chemistry training many years back now I'd be wary of nailing any explanation down here! My guess is perhaps some residual sweetness may be left if the distillation isn't 100% 'clean' (which I guess they never are? - I'm basing that on mass spectrometry analyses experience).

What further intrigues me is how sensitive our taste buds and senses may be to sugars. I'd, again, guess that we can detect it at very, very, low levels. So, perhaps it's not that much of a leap to sense we taste barley sugars in the final spirit?

@Hewie - In the link, the graph that shows vanillin in whisk(e)y is interesting. I note that Four Roses has by far the highest vanillin content. Not surprising, but interesting nonetheless.

@RianC yeah, in my thinking vanillin is a prominent flavour in the (limited) bourbon I've sampled. It definitely accentuates the sweeter flavour without perhaps the sugar it implies. Flavour is so complicated - it's hard to narrow it down to just this or that. Spectroscopic analysis is definitely enlightening (and interesting!).

I think @Hewie & @RianC are on to something.

As it happens, just last night I was listening to a lecture series on neuroscience, and the "Myth of Our Five Independent Senses" lecture touched on how the scent vanilla turbocharges our perceived taste of sweetness—even though vanilla itself is not sweet.

Assuming vanilla (like we use in cooking) and vanillin work similarly, we might have one thread in hand here. I have no idea whether they do.

@Nozinan, didn't we previously establish that barley sugar is a British candy?

connosr.com/whisky-lingo-whisky-discussion…

@Hewie, thanks much for the link. This is clearly a very complex subject. So far I haven't seen any direct addressing of the basic question, "How much of the sugars from from the whisk(e)y mash escape the fermentation process and become a tastable part of the final whisk(e)y?"

The questions remain. "Do barley sugars exist to be tasted in malt whisky?" "Does corn sweetness make it through to be tasted in bourbon?" Or are both of those just examples of reviewers making incorrect attributions of the origin of the "sweet" flavours which they encounter in the whiskies?

@Victor, are the instances of "barley sugar" you've seen possibly explainable by the British candy thing? Maybe people are talking about a particular candy in the same way someone could quote "fudge" in a review, but as Americans we don't know that candy so we think they're talking about "sugar from the original barley."

As for "corn sweetness"—if that topic came up elsewhere and I was trying to find some info for somebody, I would probably be back here on Connosr searching for a post from you. Aren't you on the record saying that unaged corn whisky isn't actually sweet, and that the sweetness in corn-heavy whisky is actually from the wood—especially virgin wood in bourbon? And so, people think bourbon is sweet due to the corn, but it's actually due to the wood? I hope I'm not sending us into a loop of circular "Victor logic" here—maybe the whole topic here is your effort to verify something you previously speculated on?

@MadSingleMalt, I really don't know about the "barley sugar" candy, whether the candy was that to which the reviewers were referring.

Yes, I have been publicly skeptical of sugar surviving fermentation to make it into the whiskey to be tasted, and did use Georgia Moon unaged corn spirit as an example of an unaged spirit with no sweetness whatsoever which I could perceive. It is precisely because I have read reference to "residual sugars" elsewhere, without any quantification or testimony as to whether they become an actual tastable component of some whiskies,..that I ask this question now. Apparently some sugar sometimes gets by those little hungry yeasty beasties. The question is still, is it enough for us to actually taste it, and make us legitimately say things like, "This bourbon demonstrates corn sweetness on the palate."? I still do not know the answer.

The question of sweet-tasting chemicals in the whiskies which are not sugars is an interesting one for what I consider the greatest new-make conundrum: oat whiskey. Every unaged oat spirit I have sampled has tasted very sweet. So far in my experience thIs has really only been the case with oats. (I have no experience yet of new-make barley-malt whisky.) I really want to know where that oat spirit sweetness comes from. I am suspecting that there is some particular non-sugar chemical in oat fermentation products which tastes quite sweet.

@Victor - I made a guess to someway answering your initial question; in that, I think some residual sugars would be left. You say you can't taste sweetness in Moonshine, well that goes some way to addressing how sensitive our taste may be to sugar i.e if we could detect such low levels you'd expect some sweetness in new make?

@MadSingleMalt - Barley Sugars can be a type of old fashioned 'sweeties' as Ralfy would say. For what it's worth, I've always thought the reference to be about the actual barley unless the word 'sweets' is added in the description.

@RianC, follow my link above and find the reference to Ralfy's review 221. I can't take time to watch it again at the mo', but my old quote is handy for now.

Of course, that's just Ralfy. Who knows what other people mean. Or what Ralfy means at other times, for that matter.

@MadSingleMalt - He does indeed use the word 'sweety' ha!

They are a bit like lemon drops, I suppose, with a slight barley funk to them. A hard candy, as you might say. On reflection, I'd say Kilkerran 12 has a fair bit of that flavour going on. Be interested to see if he references that in his review of it . . .

I've been trying to do a little digging (in between entertaining the kids). It is surprisingly difficult to find definitive info as to whether sugar is present in new make spirit. I'm pretty sure it would be in very low amounts in the wash and not be transferred via the distillation process. I skimmed through a Masters thesis which analysed single malt scotch by mass spectroscopy - lt had a long list of components identified but NONE were sugar in any form. However, a scientific article on the analysis of Shackleton's whisky showed some sugar present. This is most likely extracted from the casks (or less likely added as caramel as this was already being used at this time). As for barley sugar sweets - they were the approved sweet of the World Vision 40 hour famine which I used to do as a teenager! Yes, they are a'boiled' sweet - hard, solid sugar lumps i.e. sweet.

Some further reading:

An interesting article on the chemistry of whisky: rsc.org/images/whisky_tcm18-138981.pdf/

The effect of wood: on pg. 7 of the PDF it talks of carbohydrates and the fact that they increase throughout the maturation process - more weight to the idea the sweetness / sugar is from the wood rather than the spirit itself researchgate.net/profile/…

If distillation precludes with certainty any sugars getting through, then that would be the final answer: no sugars from the grain get into the finished whisky. But is it true that distillation does preclude that possibility? Do any sugar molecules magically hop up into the vapour condensers? Probably not more than the tiniest trace.

@Hewie So when I'm on a diet....I should drink Octomore. It's younger so it has fewer carbs?

@Nozinan ha ha bang on

I wonder if there is any relevant information on this from the world of rum distillation. With the controversy of added sugar to bottled rum, I would think there would be research into this.

If the distillate was just ethanol then there would be no distinction of flavor between grains. Most alcohol even when double or triple distilled has a significant amount of impurities that provide flavor. The distillate for bourbon can't be higher than 160 proof. That means at least 20% has to be something else. Most of that 20% is water, but water is a very good solvent and I wouldn't be the least bit surprised if some dissolved sugars and other bits from the mash came along for the ride though the still.