Canning Tomatoes - Eric E. Durnan method

Do you have questions about canning tomatoes? I did too, but got tired of all the bad information on the internet. I have been canning for over 6 years now and I have learned a lot in those 6 years, especially in the area of canning tomatoes. The one problem that I had early on was “tomato float.” This is where you can tomatoes only to find later that the tomatoes are floating to the top while you have a quarter of the jar full of water on the bottom. Some people have written that the water on the bottom is actually juice, but it isn’t. It’s water. I’ll tell you how I know.

For many years, I drove semi and hauled fluid milk and other dairy products. While a lot of the milk that I hauled went into bottling, a bunch of it went into making cheese as well. One by-product of cheese making is whey. Whey in its raw form is a nasty greenish looking water with some foam and bits of cheese. This is milk with most of the solids removed, but there are still solids in this whey. I don’t think I ever hauled a load of raw whey, but I saw what it looked like plenty of times. I went to dairies where farmers showed up to collect the raw whey to feed to hogs or spread out on their fields. This was mainly done at the smaller cheese plants that I saw in Wisconsin.

Most of the time, either the cheese plant, or a dedicated whey plant, would condense the whey down by using reverse osmosis or ultra-filtration. Rarely did I see heat used for this purpose. The water that was taken out was called “cow water” and they would pipe it down into the trucking bays for us to wash our trucks with it. I never tasted it. It was labeled non-potable, and it had a slight sheen to it when you sprayed it. In the end, it was water that was once in the cow’s udder, mixed with the milk solids.

Once condensed, the whey was transported or dried on site. Nobody wanted to ship raw whey as that was seen as shipping water. There were different levels of condensed whey. Some looked like a slightly thicker than milk consistency which I was told was equivalent to 8 semi-loads of raw whey. Then there was stuff that was nearly as thick as Elmer’s Glue which was so heavy that the tank could only be partially filled and it was a really rough trip to the processor as that whey moved around with a ton of room, and the same weight as a full load. One processor that we took this highly condensed whey to was in Colfax, Wisconsin and he told me that he liked the really thick stuff because it meant less work for him making it into powder. Since it was so thick, the sugars in the whey would separate out and stick to the bottom of the tank, necessitating a steam clean out.

Not only was whey condensed by removing water, but milk in it’s raw form is often condensed, and even canned. Often times, milk is dried all the way down to powder.

Does this mean that you can get your original product back by adding water back in? The answer in every case that I’m aware of is no. Processing changes food in irreversible ways. Whether it be dairy products, or tomatoes, once you process them, you’ll never be able to get the goodness of the original back.

When I noticed tomatoes floating in my jar, my years of hauling dairy products told me that the problem was too much water. Others make arguments about pectin, air bubbles, and a host of other reasons. Regardless of pectin or air bubbles, it’s obvious that separation has taken place and what you see on the bottom of the jar is water.

It’s for this reason that I decided to remove excess water from my tomatoes before canning. My canned tomatoes are exclusively used for cooking anyhow, so cooking my tomatoes down can either happen before or after canning, and it makes more sense to cook them down before and use less jars.

Here is my process. I prepare my tomatoes by cutting out the stem area and any other bad spots it may have. I have a pan of hot water that was boiled, then the fire shut off so that the temperature of the water is just under boiling. I dip my prepared tomatoes into the hot water for a short while and then transfer them to a strainer in my sink where the skins are removed. At this point, the tomato is transferred to another pan. Once finished, I put a lid on this pan of skinned tomatoes and cock the lid to let steam escape. I turn on the heat and bring my tomatoes up to a slow simmer and let them cook down. I mash them with a potato masher and essentially make tomato sauce, but chunky. After simmering the better part of a day, I transfer them into jars and water bath as usual. If they are low acid tomatoes, then I add a little lemon juice or pressure can 10 pounds for 10 minutes. Don’t take my word on the weight and time. I’m not the USDA. It’s just what works for my family.

We always check our jars for a good seal before opening and we always cook our canned products before consuming. If they smell or look bad, we dump them. I haven’t had that problem yet in six years with anything I’ve canned. I have had a few things others have canned and been given to me that hasn’t passed the test.

Going this route has saved me space in my pantry and the cost of many lids for many jars. I don’t get “tomato float” anymore. Cooking the tomatoes down almost sweetens the flavor as well as make it bolder and more prominent. It’s certainly not watery. Doing tomatoes this way goes well in making any kind of sauce or chili. It’s also good for goulash.

I have thought of adding other things to my tomatoes before canning, like onion and basil, but have found that the flavor changes because of the processing. I only add some salt now to my jars before canning and add everything else after I open the jar back up.