Sulfites, headaches, and the case for home-made wine

If you've ever finished a glass of red and felt the back of your skull start to throb thirty minutes later, you have probably done the same thing the rest of us did: turned the bottle around, found the words contains sulfites in fine print on the back label, and decided that was the answer. It's tidy. It's printed right there. It feels like a closed case.

It is, almost certainly, the wrong answer. We spent a few weekends digging through the actual research — FDA filings, the OIV's collective expertise document, Mayo Clinic and AAAAI consumer-health summaries, and a 2023 paper out of UC Davis that has more or less reframed the whole conversation — and the verdict is consistent across forty years of work. Sulfites cause real problems for a small number of people. Headaches in the rest of us are not one of them.

We pulled the research together into a downloadable paper you can read end-to-end. The blog post version below is the practical summary.

What sulfites actually are

"Sulfites" is shorthand for sulfur dioxide (SO2) and a small family of related salts — potassium and sodium metabisulfite, mostly — that release SO2 in solution. Winemakers add them for two reasons that have not been improved on in two thousand years: they kill spoilage bacteria and wild yeast, and they bind oxygen so the wine doesn't brown and oxidize. Roman amphorae were sanitized with burning sulfur candles. The chemistry hasn't changed; the labels have.

Yeast also produces a small amount of SO2 on its own during fermentation — usually 10 to 30 ppm. Which means there is no such thing as a sulfite-free wine. There are only wines with no added sulfites.

The number on the label, and the much bigger number in your snack drawer

In the United States, the TTB requires the contains sulfites declaration on any wine measuring 10 ppm or more of total SO2. The legal upper limit for U.S. wine is 350 ppm. The EU caps dry red at 150 ppm and dry white at 200 ppm. In practice, most commercial reds land somewhere between 50 and 150 ppm, and most whites between 80 and 200.

Now compare that to what's in a handful of dried apricots: between 1,000 and 3,000 ppm. Processed french fries can hit 200. Packaged shrimp regularly contains more sulfites than wine. Almost nobody reports a headache from any of those foods. That single observation, in a nutshell, is why the medical literature has been skeptical of the sulfites-cause-headaches story for forty years.

Who actually has a sulfite problem

Sulfite sensitivity is real and well-characterized. The FDA estimates fewer than 1% of the U.S. population reacts. Among diagnosed asthmatics it climbs to roughly 5%, and the reaction is respiratory — wheezing, bronchospasm, occasionally serious. It is not a true IgE-mediated allergy in most cases; it is a non-immune airway reactivity.

If you wheeze after a glass of wine, talk to an allergist. If you get a headache after a glass of wine and nothing else, the evidence suggests the sulfites are not what you should be looking at.

The actual suspects

Three lines of evidence have held up well, and one of them is brand new and genuinely promising.

First — quercetin and the ALDH2 hypothesis. In November 2023, chemists at UC Davis published a paper in Scientific Reports proposing that quercetin glucuronide — a metabolite of a flavonoid concentrated in grape skins, especially in sun-exposed Cabernet Sauvignon and other dark, premium reds — inhibits the enzyme (ALDH2) your body uses to break down acetaldehyde, the toxic byproduct of metabolizing alcohol. Block ALDH2 and acetaldehyde piles up. Acetaldehyde is the same molecule that makes people with the East Asian ALDH2 variant flush, sweat, and develop a headache after one beer. The Davis team's hypothesis is that the red-wine headache is a transient, drug-induced version of that same response — caused by the grape, not the preservative.

Second — biogenic amines. Red wines that have undergone malolactic fermentation contain measurable histamine and tyramine. Both are well-documented headache triggers in people with low diamine oxidase (DAO) activity. Reported histamine levels in red wine range from less than 1 mg/L to over 30. Whites are usually an order of magnitude lower.

Third — congeners and dehydration. Dark beverages (red wine, bourbon, dark rum) consistently produce more headaches than their pale counterparts. Researchers attribute this to congeners — fermentation byproducts like methanol and fusel alcohols, more abundant in dark drinks. Alcohol is also a diuretic, and dehydration alone is one of the simplest, best-documented headache causes in the literature.

So why does everyone blame sulfites?

Because the warning label exists. The 1980s FDA/TTB rule that requires contains sulfites on every American wine bottle did exactly what it was meant to do — it informed sensitive consumers — and one thing it didn't intend, which was to create a single, prominent, easy-to-remember candidate for any wine-related discomfort. Histamine doesn't appear on the label. Quercetin doesn't appear on the label. Tyramine doesn't appear on the label. Sulfites do. So sulfites get the blame. It's textbook availability bias.

Where home winemaking actually changes the picture

Here's the honest version: making wine at home does not solve a problem sulfites don't cause. What it does is hand you control over almost every variable that the research does implicate. For a sensitive drinker, that's the most rigorous experiment you can run on yourself — one bottle, one variable, at a time.

If wine gives you headaches, here's the order to try things

Forget sulfites for a minute. Try these in order — they're cheap, they're fast, and they isolate the variable that the research actually points at.

The bottom line

The sulfite warning is real. Sulfite sensitivity is real for a small number of asthmatics. The headache link is mostly cultural — a forty-year game of telephone that started with a label and ended with a folk diagnosis the science never confirmed. The current best biochemical explanation for the red-wine headache implicates quercetin, in the grape skin, not the preservative in the cellar.

Making your own wine doesn't make sulfites disappear. It does let you change the variables that look like they actually matter — freshness, varietal, additions, time-to-glass. For a sensitive drinker who has spent years assuming wine and headaches are an unavoidable pair, that's worth a Saturday and a bucket.

If you want the long version, with citations, tables, and the full regulatory background, grab the free PDF on the research paper's landing page.