National Sourdough Bread Day - Sourdough bread is full of bugs — some 50 million yeasts and five billion Lactobacilli bacteria.

National Sourdough Bread Day 2025 – April 1, 2025

National Sourdough Bread Day is an annual event celebrated on April 1 to honor the long history of sourdough bread-making. The often crusty loaf, with a chewy bite and sharp acidulated tang, is considered to be one of the most unique tasting breads available.Did you know French bakers were responsible for introducing the fermentation process that gives the bread its distinct sour taste in North America? The process of making sourdough bread was first imported into northern California during the Gold Rush before spreading through the country, following the success of the commercial production of a special yeast for it after French chemist and microbiologist Louis Pasteur discovered the microorganisms that cause fermentation and gives the bread its taste.

History of National Sourdough Bread Day

Sourdough bread-making history can be traced back to the gold rush of the 1800s that brought an onrush of miners to California — including their family members who are bakers from countries around the world. Local lore attributed the bread to Basque migrants from the Pyrenees who arrived in San Francisco during the gold rush.The bread is traditionally produced through the fermentation of the dough using lactobacilli and yeasts. In a typical production of sourdough bread, these lactobacilli outnumber yeasts by a ratio of 100 to one and cause it to produce the acids that give the bread its tartness.It starts when an ecosystem begins to form as flour mixes with water to make a starter dough. Enzymes in the flour split starches into sugars, and the bacteria convert these sugars into lactic and acetic acid as the dough begins to go down in pH level. Most microorganisms die out at this point. Before yeasts start to convert sugars into carbon dioxide and ethanol, which is often followed by gas bubbles and fruity fermentation smells that signal, it’s ready to be baked.Sourdough is considered traditional San Francisco bread, and it’s still a part of the state’s culture today. In fact, its deep-rooted history can be seen in the alias of San Francisco 49ers’ mascot nicknamed ‘Sourdough Sam.’The bread was so common during the Gold Rush that the word ‘sourdough’ became the alias for gold prospectors. Its popularity also remains today as it remains a staple on the menu of many of the state’s restaurants.

National Sourdough Bread Day timeline

3700 B.C.
Oldest Known Sourdough Bread Found

One of the oldest sourdough breads is excavated in Switzerland.

1800s
Louis Pasteur Uncovers Sourdough

Pasteur — a French chemist and microbiologist, shows that fermentation is caused by microbes like Lactobacilli.

1849
Sourdough Technique Imported

French bakers bring sourdough techniques to Northern California during the California Gold Rush.

1871
Sourdough Fermentation is Replaced

Sourdough is the main form of leavening in Europe in the Middle Ages until it is replaced by barm.

National Sourdough Bread Day FAQs

Why is sourdough bread suddenly so popular?

Sourdough bread has always been popular. Perhaps one factor helping to make it even more popular in country regions is how its fermentation process produces gas bubbles and fruity smells many consider heavenly.

Is sourdough bread good for weight loss?

Possibly. Sourdough bread has health benefits due to its fermentation process, and the friendly sugar-eating bacteria in them means eating them over regular bread may help with weight loss.

How can I celebrate National Sourdough Bread Day?

Experiment with a recipe for making Sourdough bread to celebrate the holiday. The goal of the day is to get everyone to enjoy the unique taste of the bread so, eat it.

National Sourdough Bread Day Activities

  1. Make Sourdough bread

    There’s no better way to celebrate National Sourdough Bread Day than to bake sourdough bread. If you’re new, search for recipes and follow baking instructions found in online food blogs and forums. You may even combine several recipes into one unique and distinct sourdough bread recipe for your sole amusement and experimentation.

  2. Donate to a food pantry

    If you’re convinced you’ve made the most unique homemade sourdough bread, you will most likely want to share it with friends and family and maybe even neighbors. So we encourage you to observe National Sourdough Bread Day like a few others by donating your bread to local food pantries. It’s one of the most impactful ways to honor the savory bread and celebrate the holiday.

  3. Share your recipe on social media

    Share your unique homemade sourdough bread recipe with friends online as a way to celebrate the holiday and encourage more people to try out the bread! Tag specific food platforms and popular bakeries and use #SourdoughBreadDay to post on social media to persuade them to start a conversation around your recipe or the practice of sourdough bread-making.

5 Important Facts About Sourdough Bread

  1. Its signatures sour taste and microbes

    Sourdough’s signature sour taste is a result of the fermentation of dough using Lactobacilli bacteria and yeast.

  2. It’s perfect for diabetic patients

    Sourdough is a low–glycemic food that helps to keep blood sugar levels in control.

  3. It does not require preservatives

    Sourdough bread’s fermentation process means it requires no preservative to help its shelf life.

  4. Sourdough, yogurt, and cheese

    The lactobacilli bacteria that gives Sourdough its sour taste is cousins to the bacteria found in yogurt and cheese.

  5. Lactobacilli bacteria makes it last longer

    Microbiologists believe lactobacilli bacteria also help sourdough bread have a longer shelf life.

Why We Love National Sourdough Bread Day

  1. Its tangy taste

    National Sourdough Bread Day serves as a day to enjoy the often crusty and chewy bread with a sharp acidulated tang. We love the after-effect it leaves in our mouths. It’s sweet and savory for sure!

  2. Its long history

    We love the story of the origin of sourdough bread! The practice of making Sourdough is as ancient as that of bread-making itself. Dating back more than 5,000 years. Its introduction into the culinary menu of the new world during the gold rush era in California also means it holds a significant place in our hearts. National Sourdough Bread Day reminds us of this history.

  3. Sourdough bread is fun to make

    If there’s only one reason to give for why we love celebrating National Sourdough Bread Day, this is it! There’s no doubt that even the most delicious meals would make for a dull day in the kitchen if its recipe does not lend itself to experiments that bring fun into cooking. Sourdough bread is fun to make because of its recipe and fermentation process, and we love it. Naturally, this makes us want to celebrate National Sourdough Bread Day often.

National Sourdough Bread Day dates

Year Date Day
2023 April 1 Saturday
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