07.12.06 High Alcohol & A Hot Finish
I was just today scanning the August issue of Wine Enthusiast Magazine and came across winemaker Jeff Morgan's column titled "Pride And Prejudice". He asserts that "wine police" – some buyers, writers, tastemakers – are perpetutating certain wine myths – "simplistic assumptions" – that misinform and mislead consumers: 1) high alcohol always equals a "hot" and unbalanced wine, 2) appellation is synonymous with quality – high or low, 3) sulfites are the cause of wine headaches, and 4) unfined and unfiltered wines are always better than filtered wines.I'm not going to touch the appellation question, except to say that even in France where they have the appellations controlées the origin of a wine is not an unambiguous guartantee of quality, and ceratainly not a guarantee that you will (or will not!) like a particular wine. And we have no appellation controls at all here in the good ole' U.S. of A. Heaven knows, good and bad wines can come from anywhere.
I want to speak more completely to Mr. Morgan's other three points, where my background in biochemistry and over 20 years in the industry qualify me. These are also questions – sometimes flat assertions – that I hear regularly from visitors to our Tasting Salon. So here comes the first installment of "Boring Crap You Never Wanted To Know In This Much Detail":
High Alcohol & A Hot Finish
Hooo boy – here's a goody. It is a fact that some wines do show a hot finish; no question. The question is, why. Most people assume the answer is because the alcohol content is high. To a first approximation this is a faulty assumption.
You can do the experiment yourself at home. Go to your wine store and buy five or six different bottles of, say, Chardonnay from different producers, but all with "high" alcohol contents, say, between 14.8% and 15.2%. Taste them blind. I guarantee some will be "hotter" than others.
"Alcohol" in wine is predominantly ethanol: the 2-carbon alcohol which is the primary by-product of the anaerobic metabolism of sugar by yeast. Pure ethanol does not taste "hot" – though it is astringent on the palate (if you were to drink ultra-pure ethanol your mouth would feel dry inside).
However, the "alcohol content" of a wine may also include some isomers of higher alcohols – alcohols with 3 carbons or more in their structures – which DO taste very hot. And some of the oxidation products of alcohols (ketones) taste even hotter.
In fact, it is the presence of very small quantities of higher alcohols and ketones – which are called "congeners" in distilled spirits – that make a wine taste hot.
So you are wondering why your hot wine has congeners in it. The answer is pretty simple – stressed fermentations. When yeast are stressed, they start to pump out all sorts of junk, some of which are congeners.
Yeast are neurotic, metabolicaly speaking – their normal metabolism gets stressed by a whole laundry list of things: extremes of temperature, low nutrients, high sugar, high alcohol, competition with other micro-organisms (including other yeast), natural and man-made toxins, and more, ranging from the increasingly esoteric to the downright speculative.
So here is the indirect link between high alcohol and hot taste: yeast get stressed out at the beginning of fermentation if the grapes are very ripe (cell biologists call this "substrate inhibition"), and then again at the end of fermentation by the high alcohol produced from high sugar levels (two factors here: end-product inhibition and cell membrane solubilization). Hurt at the beginning and hurt at the end. Double whammy.
And if the fermentation sticks (stops before all the sugar is used up) the yeast used to restart the fermentation are stressed from the get-go – leading to a congener production trifecta.
Heaven help us if bacteria start growing at this point. Bacterial growth will further stress the yeast (quadruple toe loop) and the bacteria themselves are capable of churning out all sorts of crud – the very infernal quintessence.
I'm not saying this happens with every high-sugar fermentation, and I've already said that not every high-alcohol wine is loaded with congeners. Savvy winemakers can minimize fermentation problems by harvesting before the fruit is over-ripe (or artfully applying the garden hose if the sugar is really high), by inhibiting growth of spoilage organisms with sulfur dioxide at the crusher, by selecting sugar- and alcohol-tolerant yeast, adding vitamins, nutrients and yeast extracts to juice, controlling fermentation temperatures, adding oxygen, and waiting to inoculate with bacteria for malolactic fermentation until after all the sugar is gone.
But there are any number of winemakers out there who are cripplingly limited by their own philosophy. They must wait until the grapes are at 29° Brix to get the flavors they want, and would never use a garden hose. They won't, or can't (as in "organic" wine production) add anything to the juice. They live by the cult of "native" fermentation. Or some believe that they have to inoculate for malolactic before the end of primary fermentation to "get it done".
I'm not being judgy and saying that any of these things is inherently bad, or good. What is certain is that these philosophical predilections can, and frequently do, result in wines with a "hotter" finish.
High Alcohol Means Unbalanced?
While twenty tasters in a room might all agree that a particular wine is "hot", men and women of goodwill may disagree on what it means for a wine to be "balanced". Balance in wine is like Supreme Court Justice Potter Stewart's take on pornography: "I know it when I see it."
I would say that a high alcohol wine needs a certain level of concentration (another characteristic that is difficult to quantify or validate) to carry off its act.
As for my own preference, those who assert that high-alcohol, high-extract, heavily-oaked wines are food-unfriendly and fatiguing to drink certainly will get no argument from me.
However, the "balance" of a wine is an individual experience and impossible to quantify, so any sort of blanket injunction against all high-alcohol wines as being inherently out of balance is just silly talk.
For the next installment of "Boring Crap You Never Wanted To Know In This Much Detail" I will tackle "Sulfites, Or Why Do I Have A Headache?"
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