A guide to canning all those tomatoes

Last night we picked 72 pounds of tomatoes from our garden.  72 pounds!  And that was after throwing out about 30% from bugs and slugs.  

They sit on the counter now, staring me down, defying me to give up probably two full summer days to magically turn them into some longer lasting option, like canned whole tomatoes, sauce, juice, or even ketchup if I'm feeling crazy.  

So I am doing the only logical thing and typing on the computer, putting off the work.

I have used a water bath canner off and on for 18 years, and a pressure canner in the past three or four years.  If you are a beginner it is best to start with a water bath canner--the processing time is longer, but the setup is pretty basic.  The best resource for water bath canning is the Ball Blue Book Guide to Preserving.  I don't know if later issues are better, but the only problem I've had with my book is the tomato recipes assume you have 45 pounds of tomatoes.  Now, my 72 pound harvest was really a freak occurrence.  Typically nobody will harvest 45 pounds of tomatoes at one time!  So, what I've learned from this book is to keep the process the same even though you might have ten twenty pounds instead of 45.   You will just use fewer jars.  (Please note that this does not apply to making fruit jams or jelly.  For those items you really need to stick with the quantities stated, but the quantities are a bit more reasonable.)

Before the 72 pound harvest I made sauce out of about twenty pounds.

20 lbs of tomatoes, truck not included

The process isn't too bad.  Rinse the tomatoes, cut out the stem part, then cut them into quarters and put them in a pot.  You have to do this in a few rounds unless you have a huge pot.

Incidentally the best cookware to use for tomatoes is stainless steel.  I've never tried aluminum but I guess aluminum reacts with the tomatoes in some way.  The Blue Book explains it.

So, cook those tomatoes for twenty minutes on medium, stirring occasionally, and then they will be squishy enough to put through a food mill.

Squishy tomatoes dumped into the food mill over a pan

I only started using a food mill in the past few years because I finally found a decent one (mine is made by Oxo, and I think even Walmart carries it now).  Before the food mill I would have to skin the tomatoes then cook them and just live with all of the seeds in a chunky sauce.  The mill gets rid of the skins and most of the seeds, leaving a much smoother sauce.  Plus it is kind of fun to use.

After several turn, the sauce goes in the pan, the skins and junk stay in the mill

After a few rounds of this, you have a giant pot of watery sauce.

Turn the heat on medium to get it bubbly, then on low.  Now you can go do something else for a few hours.  Except you want to stir the tomatoes occasionally so the bottom doesn't burn.  You want it to cook down to a thicker sauce.

I think mine took about two hours to cook down:

Yummy tomato sauce

Once the sauce is to the consistency you like, you can start canning.

Incidentally--this is the same process for tomato juice, it's just that juice isn't cooked down to a thicker consistency.


Now we must put this sauce into jars and seal them in a water bath canner.  You can find a simple water bath canner at most stores like Walmart--it is just a giant pot with a rack to hold the cans, and it should also come with a little funnel / jar grabber / lid grabber kit.


Start with clean jars, obviously, and I put the jars in the canner so they are heated in the water.

seven regular pint jars waiting to be heated

Fill the canner with water a little above the top of the jars, filling the jars as well, then put the lid on the canner and turn the heat to high.  It will take about 40 minutes to get the canner up to a full boil.  


While the water is heating up, take your lids and bands and put them in a small pot to heat slightly.  Don't let this water boil--you just want the lids to warm up.


Once the water is boiling, use the jar grabber that hopefully came with the canner to pick up each jar, carefully tip it to drain the water back into the pot, and place each hot jar on a towel.


To ensure a high enough acid level for storage you will want to put some lemon juice in each jar.  The blue book will tell you how much, depending on the size of jar, but it is usually around a tablespoon or so.  Then fill the hot jars with the hot sauce, wipe the top of the jars and put the lids on and leaving an appropriate gap between sauce and the top of the jar (1/4 inch for pint jars--see the Blue Book).  The bands should be hand tightened but not by a giant man with strong hands.  You don't want to over-tighten the lids, but tight enough to ensure a good seal at the end.  You'll get the feel for it.


Then use your jar grabber to carefully place the jars back into the pot of bubbly hot water.

The water should cover the tops of the jars by at least a half inch.  Put the lid on the canner and return to a boil.  Once the water is boiling, set the timer for the specified amount.  I believe for pints it is 35 minutes, but always check the Blue Book.


Once the timer goes off, turn off the heat, open the lid and carefully remove the jars.  DO NOT TIP THE JARS.  There will be a little water on top of the lids that will boil off.  It is important not to tip the jars because you could break the seal.

Ahhh, beautiful sauce!

As the jars cool, you should hear a "pop" when the lids seal.  When they are sealed  you should be able to press on the top and not have the top move.  A top that can pop up and down is not sealed and should be stored in the refrigerator to be used soon.

There you have it--how to turn 20 pounds of tomatoes into seven pints of sauce.  Seems like a lot of work, but it really isn't too bad.  Now, as for 72 pounds of tomatoes . . . I think I will be in the kitchen for several days.  Guess I should get started!