Preserve your fall harvest with these tips and tricks – RED. Relevant. Essential. Denver

Food and Hospitality

So. Much. Zucchini.

Every fall before the first freeze, gardeners face a surplus of fruits and vegetables from the summer growing season. An alternative to pawning them off on co-workers or attempting to eat them all at once, preserving local, in-season produce is a great way to honor the gifts of nature, cut your grocery bill and reduce your carbon footprint.     

These fermentation, pickling, canning, dehydration and freezing techniques have been perfected by humans over thousands of years and are easier than you might think.  

Jars of jam, pickles and watermelon rinds are preserved using centuries-old techniques. Photo by Amanda Schwengel

Fermentation

For centuries, we’ve transformed cucumbers into dill pickles and cabbage into sauerkraut and kimchi. Fermentation has seen a revival in the past decade, thanks to advocates such as Sandor Katz, author of “The Art of Fermentation.”  

Fermentation produces beneficial probiotics that support our microbiome, strengthen gut microflora and improve immune functions. It relies on salt to prevent harmful bacteria from growing, while allowing beneficial lactobacillus bacteria to flourish. The process is known as lacto-fermentation because it turns sugars such as lactose into lactic acid, creating that sour taste we love. 


RELATED: Recipe: ají amarillo chicken with diosa verde


Basic guidelines to successful ferments: 

  • Use kosher salt or salt without anti-caking ingredients. Anti-caking, iodine and iodide can disrupt the fermentation process.  
  • Use filtered water. Tap water is loaded with chlorine, among other substances that can also disrupt or halt fermentation.  
  • Fully submerge the foods you are fermenting in the salty brine to prevent them from spoiling.  
  • Begin fermentation at room temperature. Once signs of fermentation appear, place the ferment in the refrigerator to slow the process and maintain a crunchier texture.  

Pickling

Vinegar pickling pairs a base of vinegar with sugar, salt and spices to achieve a tangy flavor. Refrigerated pickles have not been processed through a hot-water bath to make them shelf-stable — the combination of vinegar and refrigeration safely preserves them for up to three months in the fridge. For canned pickles, the food and vinegar mixture are packed in a jar and boiled for a specific length of time at a certain temperature to kill all possible bacteria and make the product shelf-stable and easy to store at room temperature for up to a year.  

Ingredients to make dill pickles. Photo by Amanda Schwengel

For refrigerated pickles aka quick pickles: 

  • Prepare your vegetables by slicing thinly (cucumbers, squash, ginger, red onion) cutting into spears (carrots, cucumbers), peeling (carrots) or trimming (green beans). 
  • Make a brine of equal parts water and vinegar. White-apple-cider, white-wine or rice vinegar work well. 
  • Add spices such as dill, red pepper, ginger, thyme, garlic, peppercorns, etc., and kosher salt and sugar (optional). 
  • Pack the vegetables tightly without smashing them, leaving a half-inch from the rim of the jar.  
  • Boil the brine over high heat and fill the jars, leaving a half-inch at the top.  
  • Remove air bubbles and seal the jars.  
  • Refrigerate for up to three months.  
The School of Hospitality’s Paula Thomas grates a watermelon rind for pickling. Photo by Amanda Schwengel

Canning

Canning is one of the newest and most widely used preservation techniques. Highly acidic foods, such as pickles or fruit jams, are easily canned through blanching because the acid helps preserve the food. More alkaline foods, such as soups, beans and tomatoes (yes, tomatoes!), need to be pressure-canned to raise the temperature of the foods higher than the boiling point and kill any pathogens that could spoil the food, especially botulism. A great online resource for canning tips and safety measures is the National Center for Home Food Preservation.  

Canning requires a pot deep enough to fully cover the sealed jars with water and fitted with a bottom rack to raise the jar and prevent breakage, jar lifters to move the jars to and from the hot water, and a good thermometer.  

Canning tips: 

  • Fill the jars to just below the bottom of the lid ring to allow space for expansion. 
  • Remove any bubbles in the mixture before closing the jar. 
  • Secure the lid, but don’t jam it too hard to allow air to escape. 
  • Boil the filled jars for the required time based on the recipe.  
  • Adjust cooking times for high altitude.  

Drying/dehydrating

From stockfish dried by the cold winter air of the Nordic countries to tomatoes sundried under the Mediterranean sun to potato products freeze-dried in the Andes Mountains, humans have built entire food cultures from dried foods. At its most basic level, dehydrating requires little technology. A low-temperature oven can quickly dry anything from meat to herbs.  

For best results: 

  • Fruits (including tomatoes) are more suitable to drying than vegetables, most of which lose their flavor when dried.  
  • Hang woody herbs such as rosemary, oregano and thyme upside down in a well-ventilated area to preserve flavor for winter cooking.  
  • Soft-stemmed herbs such as cilantro, parsley and basil will lose some of their flavor when dried, as their essential oils are more volatile.  

Freezing  

With modern freezers, we can preserve fruits, greens, vegetables, sauces and much more.  

Freeze your harvest by: 

  • Blanching vegetables before freezing them to reduce water content. Blanching greens, for example, releases air trapped between the cells, making them greener and preventing browning. This is a must when making pesto for long keeping; pesto is not good for canning, so freezing is the best way to preserve it.  
  • Layering fruits or vegetables in a single layer to help avoid clumps of watery produce. 

Ready to pickle your heart out? Food preservation will not only help your pocketbook, it also supports the local economy, creates resilience in our communities and reduces our environmental impact. Through using these techniques, you can help decrease the number of miles food travels, which cuts down on CO2 emissions, and prevent food waste in the supply chain and your own kitchen.  

Paula Thomas is a lecturer at Metropolitan State University of Denver’s School of Hospitality. She’s an experienced food professional and educator with an emphasis on environmental, social and financial-sustainability leadership. She holds a master’s in Gastronomy in world food cultures and mobility, completed the MAD Academy Environment & Sustainability program in Copenhagen, Denmark, and participated in the 2022 James Beard Foundation Legacy Network Advisor cohort.