The sky is usually blue, the grass is usually green, and raspberries are, about 98% of the time, disgusting garbage thimbles of mold. These are all things we universally know to be true! And while the sky should usually be blue and the grass should usually be green, I’m not convinced raspberries should usually be inedible squishes of bloody despair. 

Fresh off a series of blueberry storage tests, I recently turned my attention to the little lumpy melted puddles of red manganese I love so dearly but have never been able to maintain for more than a day or two. Could there be a world in which (1) the sky was blue, (2) the grass was green, (3) and raspberries were…Delicious? Edible?? Juicy??? Easy to pick up???? Easy to pick up without accidentally splattering yourself and everyone around you????? Delicious, edible, juicy, easy to pick up (with or without accidentally splattering yourself and everyone without you) FOR MORE THAN TWO DAYS AFTER YOU BRING THEM HOME!!!!!!!????????

…There could! Step into my office.

What We Know About Raspberries and Raspberry Storage

Raspberries, like strawberries, are aggregate fruits. They are picked at the peak of their ripeness and have a famously short shelf life. (Check out this 1935 study from the University of Minnesota about these two “most perishable of horticultural crops” and how their post-picking lives compare. It’s a trippy blast to read!) 

Though they are both highly perishable once picked, raspberries are even more delicate than strawberries—a lot of the literature around storing them properly and harvesting best practices centers around their fragility. Whether this is because they are simply a more delicate fruit or because they have a gaping hole in their middles and innumerable crevices that allow for moisture and contaminants to penetrate every bit of the fruit, I cannot tell, but…they’re just tender little guys! What I do know is that I’m always disappointed by the condition I find them in if they’ve been in my fridge for more than a minute.

The Tests

Given what we know about how delicate and permeable raspberries are, I outlined a series of tests of different methods meant to combat their fleeting impermanence.

As I did with my blueberry tests, I began by separating the berries into 30-gram batches and removing anything moldy or even slightly squishy and/or leaking so as to set all these berries up for success. I compared laying the berries out in a single layer against piling them up to test whether spreading them out would keep them from disintegrating under each other’s weight. To see if I could combat their leakiness, I tested various unlined containers against ones lined with paper towels. As for extending their shelf life as much as possible, I played around with temperature and placement in the fridge to see if I could crack some kind of as-of-yet-undiscovered raspberry fountain of youth. 

I was most curious about the (below) bolded methods. The first method is what most major producers recommend for storing their raspberries; the other, the Harolod McGee method, has been proven to be the most effective berry-storing method by other powerhouses who’ve written on the subject for this very website. I tried to jostle the raspberries as minimally as humanly possible in the process of getting these experiments set up, which is what the North American Raspberry & Blackberry Association recommends for the freshest-tasting berries.

• Unrinsed, in their original clamshell plastic packaging, in the fridge
• Unrinsed, in their original clamshell plastic packaging, lined with paper towel, in the fridge
• Unrinsed, sorted by color/ripeness, in the fridge
• Unrinsed, arranged in a shallow bowl in a single layer, in the fridge
• Unrinsed, arranged in a shallow bowl in a single layer, lined with paper towel, in the fridge
• Unrinsed, in their original plastic clamshell packaging, in the crisper
• Unrinsed, arranged in a shallow bowl in a single layer, in the crisper
• Unrinsed, arranged in a shallow bowl in a single layer, lined with paper towel, in the crisper
• Unrinsed, in cardboard packaging, in the fridge
• Unrinsed, in cardboard packaging, lined with paper towel, in the fridge
• Washed in hot water, dried delicately in a colander, placed in original clamshell plastic packaging, in the fridge (Harold McGee method)
• McGee method, take two: hot water-washed, dried delicately in a colander, placed in original clamshell plastic packaging, lined with paper towel, in the fridge

The Results

As suspected, these tests went real quick. The first raspberries to go were the “unrinsed, in their original plastic clamshell packaging, in the crisper” berries—at the start of day two, I spotted mold. I also found the paper towel-lined refrigerated McGee berries to be dubious around the same time, though they held out another day before taking a tragic turn.

Everything else reached a tipping point by the end of day three. If I could go back in time—had I known that the berries would be beyond salvageable after their third day—I’d have enjoyed all the berries then.

By day four, only the following raspberries were still viable:

• Unrinsed, in their original clamshell plastic packaging, in the fridge
• Unrinsed, in their original clamshell plastic packaging, lined with paper towel, in the fridge
• Unrinsed, arranged in a shallow bowl in a single layer, in the fridge
• McGee method: hot water–washed, dried delicately in a colander, placed in original clamshell plastic packaging, in the fridge

The paper towel from the second method from the above group was completely soaked through by this point, but the raspberries had only lost about three percent of their mass. The hot water-treated raspberries were flatter and softer than the others, but they otherwise were still fine—no mold, leakage, or other signs of decay I actually would’ve loved to smash them onto a peanut butter-laden carb that day and had myself a nice little snack.

By day six, the top three tests listed above were visibly much more beautiful and intact than all the rest. The same remained true on day seven, though all of the raspberries were less vibrant than when I’d originally stored them. By the end of the experiment, husband (without knowing what the experiments were) believed the paper towel-lined, original clamshell berries were the prettiest ones of all. I found the completely untouched ones and the unrinsed ones I’d placed in a shallow, open bowl to be the ones I gravitated toward.

By day eight, everything was withering, slimy, moldy, or all of the above.

The Conclusions

…If you buy raspberries, plan to eat them within the first few days after purchase no matter how you plan to store them. From there, you have a few options:

If you’re feeling “lazy” you should be able to extend the life of your raspberries to about five days:

• Remove any moldy berries from original packaging.
• Store remaining raspberries in the fridge in the original container if it’s a plastic clamshell. If your raspberries come in a cardboard carton, you should transfer the berries to a clean, dry container. If you don’t even want to do that, you should assume you have, at most, three days to consume them.
• Rinse well (and gently pat dry) right before consuming.

If you’re feeling ambitious, you can likely extend the life of your raspberries to about seven-to-nine days:

• Remove any moldy berries from original packaging.
• Gently remove berries from their container. Double-line the container (or a shallow bowl) with paper towels. Put the berries back in the container in a single layer and refrigerate immediately.
• Rinse well (and gently pat dry) right before consuming.