Think Out Of The Jar: Canning Mushroom Soup

Cream of mushroom soup is one of those staples that you really need in your pantry. My husband likes a hot bowl of soup after an afternoon spent hauling wood or shoveling snow. A jar of soup will turn meat and vegetable leftovers into a comforting pot pie or filling casserole.

As someone who often finds herself feeding an extra five or six people at dinnertime I appreciate anything that helps me stretch a meal. But if you look at the ingredients for most commercial soup you are most likely going to find that the soup is heavy on salt and fillers like modified food starch. Monosodium glutamate and soy protein concentrate just don’t sound like food to me.

Points to Remember
I love to grow mushrooms and I love to can so it only makes sense for me to make my own soup concentrate. Here are a few things to keep in mind.

• You should not can wild mushrooms. That’s what all the canning guides say. I know my grandmother canned wild mushrooms with no problem but if there are no USDA approved guidelines then you have to assume there is some risk.
• While you can make fresh mushroom soup using cornstarch as a thickener, you can’t do the same when canning it. The high heat of a pressure canner will break down cornstarch into a really unappealing mess. ClearJel is the only thickener that will give you an excellent finished product. Unfortunately, ClearJel is not available around here. I have to order it on-line. It is a bit pricey but I use it when canning pie fillings too. The first recipe below that uses ClearJel will not work without it.
• This soup requires that you add the milk or half and half when you are ready to serve the soup—not when you can it. Dairy does not hold up to canning or pressure canning. The second recipe below is the mushroom soup recipe put out by the USDA canning website. It does not use ClearJel. The resultant soup is delicious but not as thick as you may be used to–although adding cream, milk or half-and-half to the soup when you prepare it for a meal will add texture.
• Mushrooms are low acid and must be canned in a pressure canner following the directions for your altitude.

Getting Mushrooms
You can, of course, purchase your mushrooms from the market. I would wait until there is a good sale going on and stock up. You need two pounds of mushrooms for 7 pint jars of soup concentrate, and you process the pint jars in a pressure cooker/canner.

You can also grow your own mushrooms and it isn’t hard at all, although it takes some patience. We grow shiitake mushrooms on logs down by our stream where it’s cool and damp. We also grow our own oyster mushrooms from kits. The kids love to watch the mushrooms sprout. Not only is it educational but I find my children are far more likely to eat food they have grown themselves.

Thick Mushroom Soup (ClearJel version)

Sauté 2 pounds of mushrooms in 5 tablespoons of butter. Add a cup of ClearJel, 3 quarts of chicken stock, 1-1/2 tablespoons flake salt and 5 teaspoons of lemon juice.

Pour hot soup into hot pint jars. Leave 1 inch headspace. Top with hot lids and rings and process at 10-11 pounds of pressure for 45 minutes. This will make 7 pints.

Mushroom Soup (No ClearJel in this version)

Sauté 3-1/2 pounds mushrooms and 7 finely diced shallots in 10 tablespoons olive oil.

When the mushrooms turn brown add the cooking sherry and simmer until the liquid is absorbed. Add the stock, salt and pepper and fill hot pint canning jars leaving one inch of headspace. Top with hot lids and process for 45 minutes at 10-11 pounds of pressure. Make sure that you label the jars when they cool.

Both of these recipes are flexible. If you are short on mushrooms you can fill in with some onion. If you are short on stock you can add a bit of vegetable water.

Cream of Mushroom Soup

To make recipes that call for creamed soup, add cream, half and half or rich milk to the soup as it simmers on the stove. You will need to adjust for taste here but I usually add about the same amount of milk as I have soup concentrate. Don’t boil this soup or it will curdle. You can make the soup with skim milk but I find it thin and bland. It should be rich and creamy.

I hope you always follow the canning directions in The Ball Blue Book, or the directions on the USDA canning site for all canning projects. I’ve been canning for 30 years and I still keep the directions in front of me and check off each step as I complete it. Canning is not difficult once you get the hang of it but you can never afford to be cavalier about the process. Follow each step exactly. There is a lot of research that has gone into developing safe recipes and they are designed to keep you and your loved ones protected.