Tuesday, May 30, 2017

Food Preservation Class Notes

Preserving the Harvest
For an online copy of this handout and others, go to TheRedneckHippie.com and click on the “Tutorials” tab.


Freezing
Most foods can be frozen easily preserving the texture more than canning. 
Before freezing, most vegetables must be blanched using either boiling water or steam.
Water Blanching: dunking the vegetables in boiling water for a few seconds or a few minutes. 
Steam Blanching: steaming the vegetables in a single layer held over boiling water.
What vegetable you are preserving will determine the best method and time - consult the table on the “Freezing” page on NCHFP’s website (url below). 
Once the time is up, remove the vegetables from the boiling water and dunk them immediately in either cold or ice water.
Pack into freezer bags, label with contents and date, and freeze. 
Drying
Whole: There are a lot of vegetables that are almost designed to be stored by simply drying them once they are mature: winter squash, garlic, onions, soup beans, soup peas, cowpeas, and hot peppers.  Simply let them mature completely on the vine/plant, then store indoors or out of the weather.  Beans and peas will need winnowing to remove the husks.
Sliced: Other vegetables take a bit more work to dry.  Tomatoes, green beans, peaches, apples, apricots, and many more can be washed, sliced, and dried on racks, then stored in vacuum-sealed jars or frozen.  In less humid climates, people can simply put the food on covered racks and leave them outside where there’s a good air flow.  It’s quite humid here, so using an electric dehydrator or your oven is wise.
Oven-Dried Tomatoes: Best done with small, cherry types.  Slice them in half or thirds, lay in a single layer in a baking pan or cookie sheet, and bake in the oven on it’s lowest setting until dry and leathery (Some gas stoves have a pilot light that alone will dry tomatoes overnight.).  Store in the refrigerator in a glass jar with a tight-fitting lid, or freeze. 
Leather Britches: Green beans strung on a string, ends and "strings" removed, then hung to dry until leathery.  


Canning
There are two canning processes - which type of process to use and why:
  • Water-bath canning = to preserve very acidic foods (at least 4.6pH) - heating sealed jars of food in boiling water for a specified time. Kills all bacteria and toxins except botulinum spores, so only food that is 4.6pH or more acidic should be preserved this way (that level of acidity keeps those spores dormant). 
  • Pressure canning = to preserve foods more alkaline than 4.6pH - heating sealed jars of food under pressure which raises temperatures above 212 degrees, so kills even the botulinum toxin spores. 
  • Both processes are exactly the same in their methods until you do the actual cooking/boiling. 
    Then the only differences are the type of canning pot, the amount of water in those canning pots (only 2 to 3 inches in pressure canning – completely covering the jars in water-bath canning), the application of pressure, and possibly the amount of time to process. 
Basic equipment for water bath canning
  • Ball Blue Book.
  • Large pot with lid and rack, large enough to hold jars  along with enough water to cover them well.  A pasta pot with colander insert works well for small batches, or soup pot with vegetable steamer in the bottom. 
  • Canning jars - Only use jars made and sold for canning.  
  • Rings and NEW lids - Rings can be re-used, but lids cannot (unless they are Tattler re-usables).
  • Cooking pot - Anything big enough to prepare the food you are going to put in the jars.
  • Clean kitchen towels and hot pads, spoons, measuring cups, butter knife for “bubbling” jars (working air bubbles out of filled jars)
  • Tongs for removing jars, rings, and lids from hot water - Special canning tongs are recommended for this, but you can use anything that will allow you to safely and firmly grasp and lift hot jars and lids from boiling water.
  • Stove or other heat source capable of boiling water.  Glass-top stoves are not recommended. 
  • Labeling supplies
  • Timer
  • And, of course, food to be canned
Extra equipment that is recommended but not essential
  • Canning tool kit: Magnetic lid “lifter”, canning jar funnel, canning jar tongs
  • Food mill, food processor, tomato mill, etc.
  • Water-bath canner with rack

How to water-bath can high-acid foods, step by step:
  1. Bring lids, rings, and jars just to a simmer in your canning pot, then turn off heat.  To avoid lime deposits on jars, add a cup vinegar per gallon of water.
  2. While jars are heating, prepare food to be canned according to your recipe or method:
·         Use ONLY lab-tested recipes to ensure acidity stays in the safe range, and follow them exactly.  Even something as simple as substituting “whole” for “sliced” can adjust the pH to dangerous levels later.
·         Be sure to use vinegar of the exact percentage of acidity your recipe calls for.  
·         A note about tomatoes: Some tomatoes aren’t really as acidic as commonly thought, so need acidity added to make them safe to water-bath can.  Refer to your recipe or the Ball Blue Book for specifics. 
  1.  Remove jars, lids, and rings onto clean kitchen towel laid out on counter.  Immediately fill jars, being careful to keep rims clean, leaving at least half an inch of headspace (empty space between top of food and rim of jar).  
  2. “Bubble” them, ie insert a thin utensil to work out air bubbles.  Wipe rims with clean kitchen towel.
  3. Working quickly, put lids and rings on jars, not tightening, just applying ‘til snug.  The lids and
    rings are designed to form a one-way valve, allowing pressure that builds up inside the jar to exhaust during processing (also called venting).  If you tighten the rings too tight, the jars may break or explode.  Venting is also why you leave the half-inch of headspace - so your food doesn’t get pushed out of the jars as they vent, dirtying the rim and possibly getting in the way of a safe seal forming between the lid and the jar rim.
  4. Place jars back in canning pot, making sure water is covering top of jars by an inch.  If you stack jars, don’t stack directly on top of each other: instead, place one jar “staggered” over two below so they can vent.  
  5. Cover pot, bring back to a boil and start timing.  Process (boil) for the time recommended by your recipe.  If canning in altitudes higher than 1000 feet above sea level, consult the link below about adjustments.
  6. When time is up, remove the jars from the canner to a towel on the counter.  Using towels as hot pads, tighten lids.  
  7. Let cool slowly, keeping them out of drafts (if they cool too quickly, the jars make break).  
  8. Smile as you hear the pings of the jars sealing while you’re drinking that well-earned beer to celebrate your first canning success.  
  9. Next day, test every seal (see below, under “Problems you may encounter”), then label and date all jars and store in a cool, dark place.    

Problems you may encounter
  • Jars not “pinging” when sealing -  Wait ‘til jars are completely cool (next day is good) and feel the center of the lid.  If it’s convex (“caved in/down”), your jar is sealed.  I double-check by removing the ring and trying to pick up the jar by the lid; if it holds, I’ve got a good seal.  If the jar fails any of these tests, I refrigerate and eat promptly.
  • Lime deposits on jars - Add one cup vinegar per gallon of water to canner pot before boiling jars.
  • Jars breaking - This doesn’t happen often, but it’s usually because the rings were tightened too much before processing or they were exposed to drafts or cold while still hot from the canner.  


Helpful links:

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