The story goes like this: A few years ago, I was in a program for cooks/chefs and food writers at Audrey Claire’s COOK. One of the chefs who was teaching us was a classically trained French chef (he’s American, but was trained in France and cooks French food at his restaurants). He made this bold claim: No restaurant is making French fries in house, or if they are, their fries are probably not good fries. They’re not doing it, he said, because for French fries to be halfway decent, they have to soak for at least 36 hours, and very few restaurants have room in their walk-ins for the giant vats of soaking sliced potatoes they’d need to fill fry demand. He said he didn’t know why it was such an important step, just that soaking was the only way to do it and achieve worthy results.
I’m generally not down with the word “only” but I was intrigued by his strong feelings on the matter and excited that the process he described was, basically a short ferment. I went home and immediately started playing around with this. The deep-fried Sweet Potato Fry Nests in Ferment Your Vegetables are a result of this revelation. Those party-worthy sweeties are a little sexier, a little more work, and a lot more indulgent than these which are super simple and can easily be added to a weeknight meal.
The best part about these potatoes is the texture. You know the texture of a really great, thick potato chip? Like when they have visible bubbles under the skin and the exact right bite? Think of that transformed into roasted potatoes, with crisp exteriors and smooth, puffy insides. Plus, these potatoes have the added, fermenty advantage of tang and, presumably, somewhat lowered sugar content.
This is my 2nd favorite way to eat potatoes (because mashed potatoes will win any potato contest ever and your arguments are invalid) and I’m excited to share the simple process with you.
Note: In case you missed it, these will not be probiotic after cooking. That loss is a low price to pay for this flavor and texture, IMO.
Crackly Fermented and Roasted Potatoes Recipe
I make these salty because that’s how I like them. If you need to limit salt, you can, just know that you might not get quite the same crisp (and that they won’t taste as good!). I have only tried this recipe with potatoes that I know (or have been told by a generous and knowledgable farmer) are good for roasting, but I done it with several of those varieties and the results have been consistent. If you need help picking a good roasting tater, this post might be helpful.
One other thing on the texture: these are not super creamy. The goodness of this is all about the crusty outer shell, and if they ferment for longer than 5 or 6 days, they can actually get a little hollow on the inside during roasting. I DO NOT MIND THIS AT ALL. I think it’s actually wonderful, but if you’re looking for those dinner home fries that are mostly cream with a teensy bit of crunch, look away. This isn’t the recipe for you.
One other thing on flavor: Fermented for a week or more, they become what my husband calls “tater tarts” because the acidic flavors are quite pronounced at that point. This is my preferred way to eat them, but if you stop fermentation earlier than that, you’ll still get some of those delightfully balancing acids.
1/2 gallon jar
2.5 lbs (1.13 kg) small potatoes, dirt rinsed off in cool water, skins on
2.75 cups filtered water (650 ml)
1.5 – 2 tablespoons kosher salt (27 g – 36 g, or roughly 4.1% – 5.6% in brine by weight)
3 four-inch (100 mm) sprigs rosemary, and more for garnish at roasting time (optional but delicious)
4 peeled cloves garlic, divided (optional)
2 tablespoons (30 ml) olive oil
- Quarter or halve potatoes into pieces that are roughly 1.5 inches square. Remove any eyes or greens spots, but again, otherwise keep them unpeeled.
- Mix salt into water until dissolved. Add 2 cloves of garlic into the jar and top with some potatoes. Layer in rosemary sprigs, but end with potatoes on top. Jar should be full to about 1.5 inches below the rim, or to the bottom of the threads.
- Add brine to the jar to just cover potatoes and add your weight. Once the weight is applied, the brine layer should still be 1 inch below the jar rim and no more than half an inch over the potatoes.
- Close or cover jar, according to which type of weight you’ve chosen and ferment at room temp, out of direct sunlight for 4 to 10 days. 4 days will be slightly less crisp, but they’ll have more body. 1o days will be quite sour and have a lot of puff.
- Strain off pickling liquid (feel free to use this for a large pot of soup or anywhere else you’d like salty, sour liquid, but remember it’s VERY salty compared even to normal pickle brine) and pat potatoes dry. Compost the rosemary sprigs and garlic.
- Heat the oven to 400 F and spread the potatoes in a single layer on a large, lined baking sheet. Add peeled garlic cloves and add finely chopped rosemary from another 3-4 inch sprig of rosemary, if using. Drizzle with olive oil and toss to coat. Place it in the oven for 40-50 minutes. They’re ready when they’re deeply browned and have pronounced bubbles under the skin.
- Serve as close to immediately as possible. They will stay kinda crisp in the fridge for a couple days, but they won’t be company ready again.
*Salt quantity in this recipe has been updated to reflect readers’ feedback. I tested it with lower salt and it still crisps up nicely.*
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