What Is Sturm? The Wine You Can Only Drink During Harvest

There is a wine we can only sell you for about a week, and it will not survive the drive home. That isn’t a flaw. That’s what it is.

Every autumn in Austria and Germany, for a few weeks around harvest, people drink something that isn’t quite wine yet. It’s cloudy. It fizzes. It’s sweet, low in alcohol, and it’s still fermenting while you hold it.

Austrians call it Sturm — storm. Germans call it Federweisser. Almost nobody in Canada has tried it, because it physically cannot be sold the way wine is sold.

So what actually is it?

Sturm is partially fermented grape must. Grape juice, caught partway through becoming wine, and served in that halfway state.

Normally we press the fruit, let the yeast eat the sugar and turn it into alcohol, wait for the whole thing to finish, then give it months to settle and clear. Sturm skips all of that. You catch it in the middle and drink it while the yeast is still working.

That’s why it’s cloudy — the haze is live yeast, still suspended, still eating. And that’s why it fizzes: fermentation produces carbon dioxide, and in a finished wine that gas has long since escaped. In Sturm it’s still being made, right there in the cup.

What it tastes like

Sweet, but not cloying — there’s sugar left because the yeast hasn’t got to it yet. Softly sparkling rather than properly bubbly. Grapey in a way that finished wine never is, because it hasn’t had time to turn into anything else.

If you’ve had a young piquette or a fresh pet-nat, you’re in the neighbourhood. Sturm is further up the same road — younger, cloudier, sweeter, and considerably stranger.

Most people’s first reaction is some version of what is this, followed by finishing it faster than they meant to.

The alcohol is a moving target

Here’s the part that surprises people: Sturm doesn’t have a fixed strength. It’s climbing the whole time.

Austrian wine law sets the floor at 1% — it just has to have started fermenting to count. By the time it’s usually served it’s around 4–5%. Left alone it keeps going and can reach 8–10%, at which point it stops being Sturm and starts being wine.

So the winemaker chooses the number by choosing the moment. Pull it early and it’s sweeter, fizzier and gentler. Pull it late and it’s drier and stronger. Neither is more correct — they’re just different points on the same journey.

Why you can’t buy it anywhere

Two reasons, and they’re both physics.

It can’t be sealed properly. Active fermentation makes gas. Seal it tight in a rigid bottle and the pressure has nowhere to go. In Germany it’s traditionally sold in vented containers for exactly this reason.

It doesn’t keep. Ours lasts under a day even refrigerated, and it off-gasses hard unless it’s held close to freezing. There is no shipping it, no warehousing it, no putting it on a shelf and hoping.

Which means Sturm only ever exists in one place: where it was made, while harvest is happening. That’s not marketing scarcity. That’s the actual constraint.

Everybody has a word for it

It shows up all over Central Europe, and every wine region that makes it named it something different:

Worth being precise about one thing: under Austrian wine law, “Sturm” specifically means partially fermented must made from Austrian grapes, sold between August and December. Ours is made in Hillier from Ontario fruit — so it’s the same drink, made the same way, just not Austrian. We use the word because it’s the best one there is.

What to eat with it

The traditional pairing in Germany is Zwiebelkuchen — a savoury onion tart — or roast chestnuts. The logic is sound: something salty and rich pushing back against all that sweetness.

Anything in that direction works. Salty, fatty, savoury. It is not a wine for delicate food.

When you can get ours

Only during harvest, and only in short windows — whenever fruit is coming in and something is actively fermenting. Roughly mid-September through early October, in bursts, depending entirely on what the vines are doing.

There’s no schedule we can promise you in advance, because harvest doesn’t take bookings. The honest answer is: come out during harvest and ask. If there’s Sturm, we’ll pour you some. If there isn’t, there’s a whole vineyard’s worth of things that keep better.

Frequently asked

Is Sturm the same as pet-nat?

No, though they’re related. A pet-nat is bottled mid-fermentation and then finishes in the bottle — it ends up a finished sparkling wine. Sturm never finishes at all. You drink it in the middle.

Is it safe to drink cloudy, fermenting wine?

Yes. People have been drinking it every autumn for centuries. The cloudiness is live yeast, which is the same thing that makes bread and beer.

Can I buy a bottle to take home?

Only for today. It genuinely does not keep — under a day, even cold. We’d rather tell you that than sell you something that’s wrong by tomorrow.

Will it keep fermenting in the cup?

Yes. It gets fizzier and slightly stronger as the day goes on. That’s the whole point of it.

Is it sweet?

Yes, though less than you’d expect — the fizz and the acidity cut it. Sweeter early in its life, drier later.