The difference between real sourdough and what supermarkets call sourdough

Real sourdough is made with three ingredients: flour, water, and salt. It ferments for at least 12 hours, usually longer, using a sourdough starter — a living culture of wild yeast and bacteria that the baker maintains. The long fermentation develops flavor and makes the bread easier to digest.

Most bread labeled "sourdough" in supermarkets is not real sourdough. It contains commercial yeast, rises in 3 to 4 hours, and often includes dough conditioners and vinegar for tang. The label is legal because there is no legal definition of sourdough in the United States — any bread can be called sourdough if the baker wants to. Real sourdough tastes noticeably different: tangier, with a chewier crumb and a darker, cracklier crust.

If you want the real thing, you need to know where to look and what questions to ask.

Key Takeaways

  • Real sourdough contains only flour, water, and salt, and ferments for 12 hours or longer — ask the baker directly if the label does not say.
  • Local bakeries are the most reliable source because the baker can tell you their fermentation time and starter age.
  • Farmers markets often have multiple sourdough vendors; taste before you buy to compare flavor and crumb structure.
  • Online bakeries ship sourdough nationwide, but shipping costs are high and the bread arrives 2 to 3 days after baking.
  • Grocery store bakeries sometimes make real sourdough, but you must ask the staff directly — the label alone will not tell you.

Local bakeries: the most direct source

A neighborhood bakery that bakes on-site is your best bet. The baker knows their starter, their fermentation schedule, and their ingredients by name. Walk in and ask: "How long does your sourdough ferment?" If they say 12 hours or more, ask what is in it. Real sourdough bakers are proud of their process and will tell you.

Many local bakeries sell only what they bake that day, so inventory runs out by afternoon. Call ahead or visit early. Some bakeries take orders for the next day if you want to may provide a loaf. Ask if they sell by the loaf or by weight — prices vary widely depending on size and local rent, so there is no standard cost.

To find local bakeries near you, search "artisan bakery" or "sourdough bakery" plus your city name. Check their website or call to confirm they make sourdough in-house. Bakeries that only sell packaged bread from a distributor will not have what you are looking for.

Farmers markets and pop-up vendors

Farmers markets often have multiple sourdough vendors in one place. This is valuable because you can taste different loaves and compare. One vendor's sourdough might be tangier, another's chewier. You learn what you prefer by trying them side by side.

Ask each vendor the same questions: fermentation time, starter age, and ingredient list. Vendors at farmers markets are usually small producers or home bakers, so they know their product intimately. Many will tell you when they baked the loaf you are buying — fresher is better, but sourdough keeps well for several days in a paper bag.

Farmers markets run on set schedules, usually weekly. Search "[your city] farmers market" to find the nearest one and its hours. Sourdough vendors may not appear every week, so call ahead or check the market's vendor list online.

Grocery store bakeries

Some grocery stores have in-house bakeries that make real sourdough, but many do not. The only way to know is to ask the baker or the bakery counter staff directly. Do not rely on the label or the name on the shelf.

Ask: "Is this made here, or shipped in?" If it is made on-site, ask the fermentation time. If the staff cannot answer, the bread is likely not real sourdough. Whole Foods, regional chains, and upscale grocers are more likely to have real sourdough than large national chains, but this varies by location and by individual store.

Grocery store sourdough is often more expensive than supermarket bread but cheaper than artisan bakery bread. The trade-off is that you have less control over fermentation time and less direct contact with the baker.

Online sourdough bakeries

Several bakeries ship sourdough nationwide. They bake to order, pack the bread carefully, and ship it overnight or two-day. The bread arrives 2 to 3 days after baking, which is still fresh enough to be good, though not as fresh as buying from a local baker.

Shipping costs are substantial — often $15 to $25 for a single loaf or two, depending on distance. A loaf itself might cost $8 to $12. This makes online sourdough expensive compared to local options, but it is the only choice if no real sourdough is available near you.

Before you order, read the bakery's description of fermentation time and ingredients. Reputable online bakeries list both. Check customer reviews for comments on freshness and flavor. Some online bakeries have waiting lists during busy seasons, so plan ahead.

What to look for when you buy

A real sourdough loaf should have a thick, dark, crackly crust that makes a sound when you squeeze it gently. The crumb inside should be irregular — some holes large, some small — not uniform. The smell should be tangy and yeasty, not sweet or vinegary.

Ask the baker or vendor when the loaf was baked. Sourdough is best the day it is baked, still good the next day, and acceptable for 3 to 4 days if stored in a paper bag at room temperature. Do not refrigerate it; cold starch hardens faster than room-temperature starch.

If the label lists more than flour, water, and salt, it is not real sourdough. Common additions that signal a shortcut are commercial yeast, dough conditioner, vinegar, or sugar. These are not harmful, but they mean the bread was not fermented long enough to develop real sourdough flavor.

Storing sourdough at home

Keep sourdough in a paper bag on the counter. Paper lets the crust stay crispy while the inside stays soft. Plastic bags trap moisture and soften the crust. A bread box works well if you have one.

Sourdough keeps for 3 to 4 days at room temperature. After that, it is still safe to eat but becomes hard. You can revive it by wrapping it in a damp towel and warming it in a 300-degree oven for 10 minutes, which softens the crumb and crisps the crust again.

Do not freeze sourdough unless you plan to keep it for weeks. Freezing changes the texture when thawed. If you do freeze it, wrap it tightly in plastic and thaw it at room temperature before eating.

Frequently Asked Questions

How do I know if a bakery's sourdough is really sourdough?

Ask the baker directly: "How long does this ferment?" Real sourdough ferments 12 hours or longer. If they say less, or if they cannot answer, it is not real sourdough. You can also ask what is in it — real sourdough is flour, water, and salt only.

Is sourdough from a grocery store bakery as good as from a local bakery?

It depends on the baker. Some grocery store bakeries make excellent real sourdough. Others do not. The only way to know is to ask the same questions you would ask a local baker: fermentation time and ingredient list. If they answer honestly and the fermentation is 12 hours or more, it is real sourdough.

Why is online sourdough so expensive?

Shipping costs are high because sourdough is heavy and must arrive fresh. A loaf weighs about a pound, and overnight or two-day shipping can cost $15 to $25. The bakery also bakes to order and packs carefully to prevent damage. If real sourdough is not available locally, online is worth the cost.

Can I tell if sourdough is real just by looking at it?

A real sourdough loaf usually has a thick, dark, crackly crust and an irregular crumb with holes of different sizes. But appearance alone is not reliable — some real sourdough looks pale, and some fake sourdough looks dark. Always ask the baker or read the label for fermentation time and ingredients.

How long does sourdough last once I bring it home?

Sourdough stays fresh for 3 to 4 days in a paper bag at room temperature. After that it hardens, but you can revive it by wrapping it in a damp towel and warming it in a 300-degree oven for 10 minutes. Do not refrigerate it — cold starch hardens faster than room-temperature starch.