This is the second installment of “Boring Crap You Never Wanted To Know In This Much Detail”, inspired by Jeff Morgan’s “Pride And Prejudice” column in the August issue of Wine Enthusiast Magazine. (March 2009 update appended to the end of the piece.)

In my first missive in this series, “High Alcohol & A Hot Finish” I hypothesized that a hot finish in a wine is not due to a high ethanol content, but due to the presence of small quantities of higher alcohols and ketones (congeners) produced by stressed yeast and bacteria. Turns out that this previous discussion is germane to the current topic.

Are You Allergic To Sulfites?
I hear this all the time in the Tasting Salon — “I can’t drink much wine; it gives me a headache. I think I’m allergic to the sulfites.” I don’t know how this myth got started, but I sure would like to dispel it once and for all. You are not allergic to sulfites.

At least, the chances are 100,000 to 1 that you are not. And if you are in that 99.9999th percentile you KNOW it. You knew it when you woke up in the hospital after nearly dying of suffocation from your first trip to a salad bar or your first bite of dried fruit (potentially loaded with metabisulfite, to prevent browning).

People who are allergic to sulfites go into anaphylactic shock when they are exposed to them — they choke to death. So far as I know there is no research to support the existence of a range of reaction to sulfite allergy. “Allergic to sulfites” equals anaphylaxis; no choking — no allergy.

I will allow the possibility that there could be a lesser physiological reaction, but I have not seen any sort of intermediate in myself or any of the hundreds of people I have worked with in all my years in the winery cellar. And in the cellar we not only ingest sulfites, but frequently breathe in clouds of sulfur dioxide — a much harsher test of sensitivity. Reactions may be choking and burning throat and eyes, but never headache.

You can do your own test at home (but only if you know you are not susceptible to anaphylaxis!). Light a kitchen match in a closed space and breathe in the fumes. If you develop a headache similar to the one you get when you drink wine, post a comment and let us know.

And by the way, everything fermented has a small amount of sulfites in it, because yeast produce sulfite as a metabolic by-product. Some wine yeast produce more than others. But every wine — even “organic” wines labeled with “no sulfites” — have some sulfites in them. So other fermented foods (bread, yogurt, kimchee, etc.) should give you a headache as well.

As an aside: “organic” wine — I don’t get the attraction. I know I can grow a better wine grape organically, and be more responsible to my neighbors and our descendents as a consequence. But nobody can make a better wine, nor lessen the impact of winemaking on the environment, by doing it “organically”. In fact, since organic producers can’t add sulfur dioxide to their musts or juices to inhibit spoilage, their wines are always at risk for having a higher congener content, as well as higher contents of biogenic amines (more on these below).

Do You Feel Flushed?
Some people do get flushed shortly after drinking some wine. This is a histamine response. If you are one of these people, the chances are good that this flush is more pronounced with red wines than with whites. If you are one of these folks there is a pretty good chance you have an allergy to tannins, which are more concentrated in reds than whites.

This kind of allergy is likely to lead to plugged sinuses and perhaps sinus headache. You definitely don’t want to drink alcohol on top of most antihistamines, but maybe Claritin or one of the similar anti-allergy medications might help prevent this kind of headache.

Aaaaargh! Migraine!
Wine — like all fermented foodstuffs — also contains small amounts of compounds called biogenic amines. These are related to histamine and have similar effects on the body, including causing inflammation and vasoconstriction. In some people, sensitivity to these compounds triggers full-blown migraines (you know who you are).

Even if you don’t get migraines, these biogenic amines create a physiological effect that may increase the unpleasantness of your headache. And stressed yeast (see my earlier post) pump out more biogenic amines. Your high-alcohol, native-fermented, “organic” wine is probably loaded with them.

But My Head Hurts!
In his column Jeff Morgan put it bluntly: “Most headaches are due to over-consumption — otherwise known as a hangover.” Wine is so easy to drink that it is easy to overdo it. Among the toxic effects of ethanol: it is a diuretic, and it also enhances the production of prostaglandins — the body’s pain messengers.

And then those congeners (that might be present in higher concentrations in high-alcohol wines) are even more toxic than ethanol. Congeners at very low levels are almost guaranteed to give you a headache.

So if you want to avoid this headache, first, drink less — especially if the wine has a hot finish. Second, drink water to keep from getting dehydrated. And third, take a couple of aspirins (if it is OK with your doctor!) before you go to sleep — aspirin inhibits prostaglandin synthesis.

For the last installment of “Boring Crap You Never Wanted To Know In This Much Detail” I’m going to delve into “Unfined & Unfiltered: Philosophy Meets Reality“

Update: March 2009
This piece has generated a flood of comments along the lines of: “I once ate this and this and this and this, and one of them contained sulfites, and I got a headache.” Some of these comments include the assertion “I have been told I have sulfite allergy.” I have rejected and will continue to reject publication of this line of commentary.

I am not a physician. If I was, I would not venture to make diagnoses online. I am a trained experimental scientist, and as such will say that coincidence is not the same as causation. The continued assertion that “I ate or drank something that contains sulfites and got a headache therefore I am allergic to sulfites” demsonstrates how deeply and unshakably this “sulfites in wine causes heacaches” meme has penetrated popular culture.

I am waiting for one of the “I have been told I am allergic to sulfites” comments to include “…by my physician who did his/her dissertation on sulfite sensitivities at [insert respected medical institution here].” I have not seen any such coda, and frankly don’t expect to.