Each loaf of sourdough from Harina Studio comes with a card, which you can keep and go back to whenever you're unsure of how to store and reheat your bread. It's a really handy and quick guide, but I wanted to write more about it and the reasons why it's best to store sourdough in these ways!
A quick note before I begin — Harina's cards are made with FSC-certified (Forest Stewardship Council) paper, but if you'd like less paper in your packaging or if it isn't your first time ordering sourdough, you can always opt out of receiving one. You can also click here to download a digital copy that you can save on your phone!
Shelf-Life
A lot of the bread that is most available to us, like the commercial sandwich bread you can find at the grocery, actually contains many additives. Some of these additives keep the crumb soft, some add flavor or color, and some extend the bread's shelf life for weeks!
The healthiest bread we can probably get is a loaf of sourdough. That's because sourdough loaves are made with only three* ingredients: flour, water, and salt. Without any preservatives, a regular loaf made with commercial yeast (and no added sugars and fats) would last between 2 to 3 days at room temperature. Sourdough loaves are acidic and less prone to developing bacteria and mold, so they have a longer shelf life and can keep for up to 5 days (or longer!).
Despite that, it's best to consume your sourdough loaf within 2 to 3 days — any longer, and you'll risk staling your loaf and losing its best qualities!
*But what about the yeast? Sourdough breads are leavened with wild yeast, which is cultivated using a starter — a simple mixture of flour and water.
Staling
As bread ages, it gradually loses the qualities which make it delicious. While a loaf of sourdough might taste better hours after baking, its crumb will eventually dry out, leaving us with a leathery crust, and only a hint of that identifiable sour flavor and aroma. Other types of lean bread that aren't made with sourdough can age even faster, while enriched bread (bread with added sugars and fats] tends to keep its qualities slightly longer.
A dry crumb is one of the first signs we recognize in bread that is no longer fresh. It's also what most people often associate staling with. In reality, staling isn't just a matter of moisture loss, but also of moisture redistribution — where water in the crumb finds its way to the crust, making it chewy and leathery — and a more internal process involving starches and their retrogradation. It sounds a little complicated, but what that simply means is staling is a result of starches trying to reverse back into their original state!
Starches are crystalline in their native form, and they hydrate when water is added to flour to make dough. In the heat of the oven, those starch granules start to swell and burst, turning into a gel that, along with gluten, forms the structure and shape of bread. It's often said that staling only begins after we slice into a loaf, but it actually begins once bread is removed from the oven, when the now-gelatinized starches start to cool and recrystallize, turning the bread hard and crumbly.
It's a process that happens slowly, but staling is still one of the main reasons why we end up tossing bread in the trash — either because we don't finish it right away, or because we don't store it properly. Luckily, there are ways to keep bread so they don't stale as quickly, and ways to reheat it so it's as close to fresh as we can get!
Short-Term Storage
If you'll be eating your sourdough within 2 to 3 days, it's best to keep it whole, stored in some kind of breathable material at room temperature, and sliced only when needed (make sure the cut side is down as an exposed crumb can quickly dry out). Paper bags, like the thick kraft bag that Harina sourdough loaves are packaged in, are a perfect choice for storing your bread! You can also use a towel or beeswax-coated cloth to wrap your bread, or simply place it in a bread box.
Wrapping an unsliced loaf in plastic is alright if you plan to reheat your bread the next morning — the crust will definitely soften, but it's possible to make it crispy again by reheating it the way you would a thawed loaf. Otherwise, I don't recommend storing sourdough in any kind of plastic (whether it be plastic wrap, a Ziploc bag, or a Tupperware) for any longer. Like mentioned above, water from the crumb will find its way to the crust, making it chewy and leathery. Storing your loaf in plastic will only contribute to this, and the moisture it traps can lead to mold growth*, which tends to happen quickly in warm and humid environments like ours!
*Bread fresh out of the oven is sterile. Mold spores, however, are present in the air and even on our hands! They can land on bread and multiply, given the right conditions. If you see mold on even a single slice, it's best to just discard your entire loaf as some species of mold produce dangerous toxins — though you might only find fuzzy spots of fungus on the surface of your bread, its microscopic roots have likely already spread!
Long-Term Storage
My favorite way of storing sourdough, even if my family and I plan to eat it soon, is in the freezer. It's also the best way to keep your bread as fresh as possible, as the freezer's low temperature slows down the starch from recrystallizing, almost to a complete stop. It might seem like second nature for some to store bread in the fridge, but this is something you should never do, as staling happens most rapidly at those temperatures!
If you want to save your loaf for later, freezing will keep it fresh for up to 1 month, and sometimes more. Freezing is not without its problems though! It's a good idea to consume your bread within that time, as frozen bread can still deteriorate. Too long in the freezer, and you might get a loaf with a dry and shriveled crumb, little flavor, and less of that fresh bread smell.
Another thing to look out for is freezer burn (signs of which are discoloration and a "freezer" taste), but this is something that's easily prevented, as long as your bread is properly protected! Whether your loaf is whole or sliced, make sure you store it in a thick freezer-safe plastic bag, like those sold by Ziploc. It's not something I always do, but it's always a good idea to separate slices with layers of parchment or freezer paper, so you won't have to worry about slices sticking together.
Reheating
You can reheat your sourdough slices any way you like, and to whatever degree of toastiness you prefer! The easiest way to do so is using a toaster, but keep in mind that some toasters are too short for a whole slice of sourdough, so you might need to cut your slices in half. You can also toast them in the oven, or on a skillet.
Frozen slices don't need to be defrosted before reheating, but whole loaves do, so you'll have to plan ahead if you're going to reheat one — whole loaves can take anywhere between 1 to 3 hours to thaw. Just leave your loaf at room temperature until the center is no longer frozen solid (you can use a skewer or small knife to check), then reheat it for 10 to 15 minutes in an oven preheated to 350°F (175°C) until the crust is crispy. You can also reheat unsliced, room temperature loaves in this way, as long as they haven't dried and gone stale. Don't forget to let it cool a bit before slicing!
Spritzing some water on your loaf right before reheating it is something you can also do — this step isn't necessary, but a light spritzing will create a bit of steam that will help crisp up your crust. Lastly, if you thaw a whole loaf with plans to slice it, a good trick is to cut it while it's still cold. You'll get cleaner slices, and it won't take as long to reheat!
References
Cote, J. (n.d.). The Science Behind Bread Staling. BAKERpedia. Retrieved July 20, 2021, from https://bakerpedia.com/the-science-behind-bread-staling/
McCulloch, M. (2019, February 22). Is It Safe to Eat Moldy Bread?. Healthline. Retrieved July 20, 2021, from https://www.healthline.com/nutrition/can-you-eat-bread-mold#discarding
Migoya, F., & Myhrvold, N. (2017). Modernist Bread. The Cooking Lab.
Staling. (n.d.). BAKERpedia. Retrieved July 20, 2021, from https://bakerpedia.com/processes/staling/