Preserving the Harvest

A typical day’s harvest in August.

Summer is ending. The nights are cooler and followed by heavy morning dews, summer vacations have come to an end, lakes are closed for swimming…but the garden is still in full force. Many favorite garden crops are just coming into their own in the late summer—corn, big heirloom tomatoes, spicy hot peppers and ripe sweet peppers, bouqets of aromatic basil and tender eggplants. By early September, fall roots, like carrots and beets have reached full size, leeks are ready for harvesting, and greens are looking lush, benefitting from the cool evenings.

Now it’s mid-September, and we’re in the thick of putting up the harvest for winter and early spring eating. We start preserving as early as May—with rhubarb—and there’s always some local crop in abundance throughout the summer—berries to jam, early greens to freeze, spring turnips and summer cucumbers to pickle, etc. But late summer and early fall are really when our pantry and freezer fill up. Currently, we’re freezing chard, canning all things tomato (barbecue sauce, crushed tomatoes and salsa this week), and fermenting the last pickling cukes and chinese cabbage (as kimchi along with some scallions and carrots from the garden). It’s the sixth straight week canning tomatoes.

Tomato Sauce cooling .

I always start by getting in some basic staples to use as ingredients in cooking: tomato puree, unsweetened apple sauce, frozen berries, herbs chopped and frozen in silicone mini-cupcake trays. These are easy to prepare and fill the pantry fast, and you can’t help but appreciate their versatility. But there are so many delicious recipes that can be preserved! Home-made convenience foods–like  pasta sauce, barbeque sauce or salsas, rich herb pestos and thai curry pastes (which we started freezing after adding lemongrass to our garden), spicy pickled corn and Italian-style marinated peppers–can be put up in big batches to have available through the off-season. These are the preserves that are particularly enticing to make and add that extra kick to meals on dark, cold winter days (and without any disposable packaging!).

To best capture the flavors and nutrients of the fresh harvest, it helps to choose your preservation method wisely. Fermentation, freezing, canning and dehydration can all work well depending on the crop and recipe. Here are some tips on which method to use for which situations.

Dehydrate It

Freshly harvested golden oyster mushrooms.

This is the method I use the least. It’s not nearly as good as the others for preserving nutrients. So, why choose it at all for your precious home-grown produce? Because, it’s simply the best method for preserving things for extremely long periods of time. It’s generally recommended that you consume most canned or frozen foods within a year or so (although some of that advice may be overly cautious due to a lack of research on the actual storage life of various products). But there’s plenty of research showing that properly dehydrated and stored foods can last for a decade or longer. The organisms that cause spoilage (bacteria, yeasts, molds) require water to survive. No water, no spoilage. So, shelf life is one reason to dehydrate.

Dried peppers ground into chili powder.

Another reason is that certain foods have a better texture and intensified flavor when dehydrated versus other methods of preservation—for example shiitake mushrooms. Many mushrooms turn to mush when frozen, and would need to be pickled or pressure canned to preserve through canning, but store and retain excellent flavor for years when dehydrated. We’ve found that the golden oyster mushrooms we’ve been cultivating store well dehydrated and are excellent in winter soups. Many herbs, both culinary and medicinal, also store well dried (for teas or cooking). We often dry herbs like oregano, basil, mint, and lavender.

A final reason to dehydrate is that some recipes work better with dried products–for example dried chili peppers can be used to make your own custom-blended chili powder, and dried fruits are perfect for home-made granolas. You can find an excellent introduction to dehydration from Virginia Cooperative Extension here.

Freeze It

Curry paste, pesto or chopped herbs defrost quickly if frozen in small cubes.

This is my absolute favorite method for preserving fresh flavor, and in most cases does the best job of preserving nutrients as well, especially for greens, as well as berries and herbs (like cilantro) that lose their characteristic flavor when dried. Of course, texture suffers, but that’s often not a problem. Freezing and thawing breaks the cell walls and softens foods in a similar way to cooking, so the difference in texture will be less noticeable in foods that will be cooked anyway, or if you use them while still partially frozen (like for smoothies). It’s so handy to have pre-washed and chopped vegetables ready to pull out of the freezer and add to recipes. Vegetables like corn, carrots, green beans, etc. are blanched just a couple of minutes to stop natural enzymatic processes and retain excellent flavor when frozen. University of Georgia has a great primer on freezing vegetables, and this factsheet from University of Minnesota has some excellent tips and background on freezing produce.


Hot pickled corn, from the Tart and Sweet cookbook.

From pickles like hot pickled corn and marinated peppers, to tomato sauces, or jams and juices, canning is an effective way to preserve a wide range of flavors that are ready to open and consume anytime and easy to store. Boiling water canning is only appropriate for high-acid foods (pH less than 4.6), which is why tomatoes, fruits and pickles are so popular. For low acid foods, pressure canning is the only acceptable canning method to achieve a shelf-stable product. That’s why for plain vegetables I prefer freezing, so they don’t have to be cooked into oblivion in a pressure canner. But most pickled products and fruits only need to be processed 10-20 minutes. And many tomato-based products, like pasta sauce or barbeque sauce, would be cooked for a long period of time anyway to thicken them, so processing in a canner isn’t really compromising on the texture, flavor or nutrient content.

The actual process of canning is quite simple…if you can boil water, you have the skills required to can your produce! It’s also necessary to pay attention to recipe proportions, timing and cleanliness, but there’s really nothing complicated about it. And these days, there’s a wide variety of recipes available beyond traditional canning resources, from recipe books on small batch canning or specialty pickles to blogs and webinars that make canning more accessible than ever. I love to check canning books out of the library during the winter to browse recipes. The National Center for Home Food Preservation has all the basics on both boiling water and pressure canning at their website as well as many basic recipes.

Most of our modern food preservation techniques are about eliminating bacteria, killing microorganisms and creating a sterile environment. Can you really just leave food in a jar on your table and have it increase in nutrition and flavor? Yeah, that’s pretty amazing. The magic of lacto-fermentation is that you create an environment in which good bacteria can grow, but harmful bacteria cannot. This is achieved through salt. Salt and sugar are often used in food preservation, because they bind water and make it less available for micro-organisms. Salt is used in lacto-fermentation because harmful bacteria can’t tolerate high salt environments, but some of the healthy bacteria (like lactobacillus) can. Once the harmful bacteria have been eliminated, the friendly ones can take over. They make lactic acid by consuming the natural sugars present in the produce, which preserves the nutrients, flavor and texture of the vegetables being fermented.

A glass jar filled with water will be placed on top of the kimchi to keep ingredients submerged and prevent spoilage from air contact. Note: no liquid is added, it’s just released from the cabbage after salting.

Some of the traditional fermented products we like to make include kimchi, sauerkraut, cucumber pickles, and hot sauce (from fermented hot peppers and garlic). The thing I love about fermenting…aside from the flavors…is how easy it is. At the end of the summer, when there are too many hot peppers, and I’m tired of processing, I can just cut off their stems, toss them whole into a jar with a few cloves of garlic, cover with brine and let them hang out on the dining room table for a month (covered with a cloth to keep out dust and flies). They do need to be checked periodically to skim any scum that forms on the surface to prevent it from suffocating the good bacteria (daily in hot weather, every few days in cooler weather).

Once the process is done (timing can vary a lot depending on size of the produce and air temperature), fermented peppers can be stored in the fridge and used in cooking, spooned over tacos, added to sandwiches, or pureed to make a delicious hot sauce. If we ferment late in the season, we often leave finished products on our unheated back porch. As long as the temperatures stay low but above freezing (cooler than 50°F), fermentation will slow or stop altogether, and they store quite well without taking up fridge space.

It’s hard to do better than Sandor Katz’s infamous guide to fermention, Wild Fermentationfor an introduction.

Join us For a Small Batch Preservation Session
If you’re new to food preservation and want some tips, are looking to expand your skills, or just want to exchange ideas with fellow local foodies, join us for a small batch food preservation session on Saturday, October 20 (Tomatoes) or Saturday, October 27, 5-7 PM (Fall Fruit – apples or pears). We’re keeping sessions small, to fit in our kitchen, and so that we can personalize the experience and answer all your preservation questions. We’ll can something together, review basic tips and process for canning, answer questions on other methods, and share samples of some of our products and our favorite food preservation resources. RSVP at least a week in advance if you’d like to help choose the recipe to be used. Each participant will be able to take a jar home. We’re asking for a $20 donation per person, but open to trades (contact us ASAP if you want a non-traditional arrangement!).

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