Food preservation methods: Root cellaring

We’ve had questions from new CSA members regarding home food preservation techniques and any relevant items that might make good holiday gifts. We’re thrilled that folks are thinking ahead to preserving next year’s bounty, as that’s the key to getting the most out of a CSA and building the economic sustainability of local foods in general. This series will present some of our experiences and advice, along with ideas for kitchen items that we’ve found to be useful investments as serious practitioners of home food preservation.

ROOT CELLARING & WINTER STORAGE
Many kinds of produce and foods are reasonably stable on their own, if given the proper conditions. Traditional farms and homes used various forms of a root cellar, generally a room dug into the ground (or a retrofitted basement) which used the ambient ground temperature and humidity to keep foods in proper conditions for long-time storage. As in other topics, there is a ton of information available in books and online, so we’re going to focus on the ways we handle this process.

Choosing storage varieties:
There are many different varieties of any given produce item, with different culinary and storage properties. For exampe, Arkansas Black apples are virtually indestructible, while others may last only a few weeks (see this publication from Iowa Extension for examples of apple storage qualities). Potatoes, garlic, onions, and many other storage crops are the same way. If you’re buying (or planting) items intended for storage, do some research and ask some questions first. If the grower has no idea, that may be a hint that they don’t store food themselves and maybe aren’t handling the food properly for storage either (see next).

Preparing storage items:
In some cases, like apples, the product is pretty much ready to store as-is, assuming you establish the proper conditions. Onions and garlic need to be cured first, a process of hanging the fresh crop until it dries enough to become shelf stable. Most of the time, you buy these two in this condition anyway, though it’s worth being aware of the season and asking the grower to ensure they’re actually properly cured and not fresh. Other things, like sweet potatoes, are often sold “fresh” at farmers markets but will benefit greatly from proper curing before sale, and will then store much longer and taste much better. In these cases, curing involves storing the items for a certain length of time at fairly warm temperatures to allow certain natural chemical changes that enhance stability and flavor.

Storage locations:
Selecting the proper storage location begins by researching what “ideal” storage conditions are for a given item (in terms of temperature & humidity), then finding the closest conditions that reality will permit. Knott’s Handbook for Vegetable Growers, p. 432 & 433, is our reference source for storage conditions. For long-term storage, temperature stability is a plus; temperature swings will reduce the storage life of produce (this is why garages aren’t ideal). For example, garlic begins to sprout if temperature fluctuates regularly; sprouting is desired from the October-planted garlic in the ground that will be next year’s crop, but the garlic that we want to keep eating into March needs to be tricked into thinking that it’s not time to grow yet, and stable temperatures will help. Sweet potatoes like it warm and will start to go bad if they get too cold. Most other storage crops are happier in cooler conditions. We don’t have a proper root cellar, dug into the ground to ensure high humidity and temps just above freezing all winter, though it’s a someday-project. It’s also possible to construct a basement version, in effect a cold-storage room that stays colder than the basement itself (see these articles from Mother Earth News on building a proper root cellar and a basement version).

We do, however, have a house that is larger than we need, and whose back rooms we hardly ever use and thus don’t heat or cool artificially. So for years we’ve used the back “master” bedroom as an excellent root cellar, as it tends to remain between 34-40F throughout the winter, given the large buffering presence of a basement underneath and well-insulated walls. Apples, garlic, onions, and more do well back there, the former in crates or boxes and the latter hung in bundles or spread on wire racks. Other items store best at warmer temperatures, like sweet potatoes and winter squash, and we store these in the house itself, often in the same room we cured them in originally. Darkness is important, too: daylight will encourage sprouting or other unwanted developments.

Storage time:
We don’t always intend our storage items to last a really long time, given that we also preserve lots of food in other ways. In most cases we shoot for things like apples, potatoes, and squash to last us into January, at which point we can start dipping into more canned and frozen foods for the next few months. Garlic and onions usually last us into March with some attention. It’s important to check your storage items regularly, and use anything that’s starting to sprout or otherwise go bad. You can’t predict ahead of time which onions will sprout in January versus March, but regularly checking and using the ones just showing some green will naturally cull the supply without much waste.

If you take your home food supply as seriously as we do, refusing to buy produce from off the farm year-round, you quickly realize that the “hungry” months aren’t winter, but spring. We still have plenty of food on-hand in the depths of February; it’s the warm rainy days of March through May in which food supplies are actually the thinnest. By this point the only fresh food is lightweights like salad greens and radishes; you still have months to go before the heavy hitters of summer and fall show up again. This is why we use root cellaring as a complement to other preservation methods, as a way to delay the use of longer-term storage items. Our special Mercuri winter tomatoes are the same way; we don’t expect them to last all year, but we do expect them to keep us out of the canned tomatoes for a few extra months, thus saving the need to do extra canning during the already-busy season.

Salvaging stored items:
When you do notice stored items starting to sprout or go bad, there are many ways to salvage them before loss. Sprouting onions can be cut up and dehydrated, an easy task for a cold February day. Now you have onions for much longer, without doing all the work in busy onion season. My favorite trick for saving sprouting garlic is to steam-roast large batches, then freeze the pulp (a trick I learned from a Michael Ruhlman cookbook). I pack a glass baking dish with sprouting garlic heads, pour a little water in the bottom, cover it with foil or a lid, and roast for an hour. Then I squeeze all the soft, aromatic garlic pulp into a dedicated ice-cube tray and freeze it, creating little “bullion” cubes of pure roasted garlic that add great flavor to soups and sauces for months past the expiration date of the whole garlic. Mid-winter squash or sweet potatoes can be cooked up into pulp, then frozen, replacing empty spots in your freezer where you’ve started pulling out other items. Mid-winter apples turning brown can still be made into applesauce.

All of this could  be done in the fall, but that’s when we’re already too busy preserving food that has to be dealt with then, and still actively farming. If nothing else, cellaring/storage is a way to delay some of that preservation work a few months, spreading it out so it’s not so overwhelming, and extending the storage life of these items. At best, it’s an easy way to enhance the diversity of your winter menus with food that took little to no preservation work, simply the dedication and planning required to acquire and store fresh local food when it’s available.

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