How to Make Sourdough Bread More Sour Tasting

It seems the vast majority of hobby bakers don’t mind a nice mild-flavored loaf of sourdough bread. When it’s less sour, homemade bread pairs fabulously with a wider variety of toppings, add-ins, and meals. It’s good news for these folks that most homemade sourdough bread isn’t very sour at all! In fact, it is significantly more challenging to make sourdough taste more sour instead, leaving certain new bakers feeling bummed their bread isn’t living up to their expectations.

Is your palate craving an extra tangy loaf? Read along to learn how to make sourdough more sour. This article will cover 10 ways to manipulate your starter, dough, and baking process to increase the sharp notes in your homemade sourdough bread. But first, let’s review what gives sourdough that classic tart flavor in the first place!

What Makes Sourdough Sour?

Sourdough gets it name because it’s fermented, not because it’s always inherently sour-tasting! Chances are you’re already familiar with how sourdough works, but here’s a quick recap just in case: A sourdough starter culture is made up of wild yeasts and beneficial bacteria, namely lactobacillus or ‘lactic acid bacteria’.  When those organisms are ‘fed’ fresh flour and water (such as by feeding a sourdough starter, or adding active starter to a larger volume of dough to make bread), they initiate a fermentation process that converts the starches in the flour into various byproducts. 

Carbon dioxide is one byproduct of the fermentation process, which helps the bread rise to have fluffy, airy texture. Lactic acid and acetic acid are also produced, and are responsible for the complex flavors in sourdough bread. Lactic acid offers a more mild, tangy, yogurt-like flavor. On the other hand, acetic acid provides a more sharp, sour, vinegar-esque taste. The amount or balance of these two will dictate just how sour your bread tastes, which is what we’ll learn to manipulate with the tips below! 

To make your sourdough more sour, the goal is to increase the overall content of both acids – but primarily acetic acid. 

Where you live also plays a huge role in your sourdough journey. Different strains of wild yeast and native bacteria unique to your area will make their way into your starter and influence its flavor. That is why it is nearly impossible to replicate that quintessential San Francisco sourdough flavor… anywhere but San Francisco! Even when folks purchase a little piece of our organic Coastal California sourdough starter, it will eventually evolve to taste different than ours depending on where they live. 

10 Ways to Make Sourdough More Sour in Flavor

Use the following tips to alter the content of various acids to make your sourdough more (or less) sour. Feel free to use one or a combination of these techniques, though I suggest starting with tweaking just one factor or two at a time, as opposed to changing 6 things at once! While experimentation is great, just like in a laboratory (or garden), altering more than one variable at once will make it difficult to determine which step contributed to the desired result the most.

In addition to flavor, keep in mind that all of these things can also influence the rise of your final bread loaf, so some trial and error may be necessary to get it just the way you like it!

1) Use More Whole Grain Flour 

One easy way to make sourdough more sour (and noticeably so!) is to incorporate more whole grains into your sourdough recipes. Flour made from whole grains such as whole wheat, einkorn, and rye naturally have more robust, tangy flavors than white flour. Rye especially. Even better, acid-producing bacteria love whole grains and will thrive! You can also switch to feed your sourdough starter with whole wheat and/or rye flour, or at least a portion thereof. Our starter becomes significantly more active that way!

The only drawback is that whole grains can make sourdough bread more dense.  I suggest adjusting various recipes and slowly increasing the ratio of whole grain flour to white flour. For instance, our go-to simple sourdough bread recipe already calls for 65% white bread flour, 30% whole wheat flour, and 5% rye. You could start there, and gradually swap out some white flour for more whole wheat or rye until you find the sweet spot you’re after – where it tastes great, but is still fluffy enough for your liking. Bonus: you’ll also benefit from the added nutritional value and fiber found in whole grains. 

2) Ferment Dough Longer

The longer you allow raw dough to proof and ferment, the more lactic acid and acetic acid will develop. Thus, the increasingly tart it will become! Additional time during cold ferment is especially effective at making sourdough more sour. In our basic sourdough bread recipe, we already recommend letting the dough bulk ferment at room temperature for at least four hours, and then putting it in the refrigerator to cold proof overnight (about 8 hours). You can experiment with extending the cold proof time even longer, for 24 to 48 hours.   

The one caveat here is that dough can potentially overproof and fail to rise as nicely after a very long fermentation time. Perhaps you’re willing to sacrifice some fluff for a little more acid? Another way to make sourdough more sour is to let refrigerated dough sit out at room temperature for 30 to 60 minutes before baking, but that too can negatively affect “oven spring”. (You get the best oven spring by quickly transferring cold dough into a preheated hot oven). 

When it comes to potentially over-proofing dough, sourdough focaccia will be more forgiving than a standard loaf! Focaccia is already extra bubbly and more flat by design. Try developing more sour flavors through extended cold fermentation with our simple sourdough focaccia recipe.  

3) Store Your Starter at Room Temperature

Years ago, I heard a piece on NPR’s “Science Fridays” that explained how your starter will change flavors depending on how it’s stored. Lactic acid bacteria thrive in a cooler environment, so refrigerated starters will be more mildly tangy. In contrast, keeping your starter at room temperature will encourage more acetic acid and sharp, vinegar-like notes. Therefore, try storing your starter at room temperature to make your sourdough more sour. It will take some time for it to adjust and shift to a predominantly acetic acid culture, so you’ll need to consistently store it at room temperature.

However, keep in mind that the feeding schedule and maintenance will be different. Mature refrigerated starters can go weeks to months without feeding, while sourdough starter that is kept at room temperature must be fed more often to survive. Most experts say to feed room temperature starters daily. But read the next tip below first… When it comes to achieving sour flavors, less feeding is more!

4) Feed the Starter Less (and keep the hooch) 

If you feed your sourdough starter very frequently, the acids that give it a great tang don’t have the opportunity to build up. So, starving your sourdough starter a bit can make it more sour! Not enough to kill it of course. But if you store your starter at room temperature, try going a few days between routine feeding instead of daily. In the fridge, skip a week or two here and there. If it develops a layer of hooch (that dark liquid that develops when a starter is hungry) stir it in rather than pouring it off as you might normally do. Also note that the more established and mature your starter is, the more sour it will become. If you’re working with a new starter, be patient with it!

5) Add Your Starter After Peak

Most sourdough bread recipes say to use or add your sourdough starter in with the other ingredients when it has reached “peak activity”, ours included. Peak activity occurs after a sourdough starter has been fed fresh flour and water, has risen nicely (at least double in size), is no longer obviously growing, but hasn’t yet started to deflate. During that time of growth, the yeast and beneficial bacteria population is feeding and rapidly multiplying. 

If you use your starter before it reaches peak activity, it has developed a less robust microbial population – which can lead to a less vigorous bread rise. Try waiting to use your starter until after peak instead, when it has just started to deflate again. At that time, there are as many beneficial microbes present as possible, they’ve turned the starter nice and tart, and they’re starving for more! They’ll feed on the fresh flour in the dough with the appetite of a stray cat. Don’t wait too long past the peak though. The microbial population will decline when the starter completely deflates back to the starting point.

6) Keep Your Bread Basic 

You really only need three things to bake sourdough: flour, water, salt. Add-ins like nuts, seeds, cheese, herbs, or olives are delicious and fun (and quite welcome, IMHO!) However, additional ingredients (especially fats) can “distract” the beneficial bacteria and yeast away from further fermenting the starches in flour into sour-tasting acetic acid. So, if you really want to make your sourdough more sour, keep it simple.  (This doesn’t apply to focaccia though, since the toppings are added right before baking.)

7) Add Citric Acid, aka Sour Salt 

Citric acid is naturally found in citrus and also manmade to use in food, cosmetics, medicine, and more. Also known as “sour salt”, citric acid is often used in home canning to lower the pH and safely preserve foods. Turns out, you can also use citric acid to make your sourdough bread more sour! 

Now, some sourdough purists may turn up their noses at this idea, and it’s admittedly not as traditional as the other flavor manipulation methods on this list… but it works! In fact, this could be one of the easiest tweaks for someone who lives in a climate that simply won’t produce the tangy sour flavor they hope for, despite other efforts. Combined with a long ferment, you’re still getting all the wonderful health benefits of a long-fermented sourdough loaf, along with a sharper flavor.

A friend of mine uses this trick. I’ve tried her bread and it tastes awesome! She adds about 1/4 to 1/2 tsp of citric acid to the dough, using this well-rated food-grade citric acid. Since we haven’t done this ourselves yet, I don’t have incredibly detailed tips to offer. We plan to give it a try soon, so I will report back! Because citric acid is indeed a weak acid, do use some caution: avoid getting it in your eyes, and wash your hands after handling it.

8) Maintain a Stiff Starter

Apparently, a drier environment promotes more abundant acetic acid production. On the flip side, our lactic acid buddies like it wet. So in an effort to increase acetic acid content, try maintaining your sourdough starter on the dry side – also known as more “stiff”, or at a lower hydration ratio. 

Feed your starter as you normally would and then slowly incorporate more flour, one tablespoon at a time, until it has reached a consistency where it can still mix and move without turning into a solid clump of dough, but definitely isn’t runny or pourable. Take note of the flour amount for next time. I’ve also found that stiff starters take longer to reach peak activity, and stay peaked longer, which will also help sour flavors to develop.

9) Use Less Starter 

We personally love to add plenty of starter to our sourdough (and admittedly add even a little more than our own recipes call for!) Adding ample sourdough starter can shorten the proofing time, and also allow the dough to rise nicely even in cooler conditions. However, a high ratio of starter-to-flour speeds up the fermentation process which can make sourdough less sour-tasting. Instead, if you cut back on the amount of starter added to your dough, it will actually force the limited population of bacteria and yeast to feed more on the dough itself. It will also likely take longer to proof and foster a lower hydration environment as mentioned in previous tips – both of which also make sourdough more sour. 

10) De-Gas the Dough

The final tip on this list of ways to make sourdough more sour is to de-gass your dough. “Degassing” is the baker’s term for removing air bubbles from the dough. Yes, small air bubbles are ultimately desirable in your final loaf, but they need to be moved around and manipulated while the dough is proofing. 

As air bubbles are knocked out, it reinvigorates yeast cells, moves the microbes around, introducing them to new food, and overall leads to improved fermentation. It also helps to create a desirable “crumb”, where small air bubbles are evenly distributed across the loaf of bread. (Not degassing can lead to huge air holes and uneven denseness of bread)

One way to degas bread is to punch down the dough once or twice before the final shaping of the loaf. Another effective method is by folding the dough. In our simple sourdough bread recipe, we advise to complete several rounds of “stretch and fold” early in the fermentation stage, and again before shaping the loaf (before it goes into the fridge to proof overnight).

And that is how to make sourdough bread more sour!

Who else is officially hungry now? In addition to activating your appetite, I hope this article taught you something new! As you can see, there are several ways to increase the sour flavor of sourdough bread – so have fun experimenting! I’d love to hear what works best for you, so please come back by to share your success stories or feedback. Also, please pin or share this article if you found this information to be valuable! Thank you so much for tuning in.

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