Wednesday, August 25, 2010

Hands On - Canning Tomatoes

Are you ready?  We are going to learn how to can tomatoes -- using the boiling water method - with halved or quartered raw tomatoes with no added water or juice.  I will attempt to explain every step - but if I am not clear or you want more details, then see the USDA's guide to canning tomatoes.  It can be found at this link.

Or you can look at the Ball canning instructions, which are a little shorter and simpler.

1.  Start with the best ripe tomatoes you can find.  Some people prefer the meatier Italian plum or roma type tomato for canning.  Others like the "round kind".  The most important thing is that they be ripe (not overripe) and flavorful.  Featherstone CSA members can order preservation shares - e mail or call Becky at the farm- 507-864-2400 for details.  You will need about three pounds of tomatoes per quart jar.  Depends on how much trimming is necessary. One bushel of tomatoes weighs about 53 pounds and the U of M publication I have said you would get from 15-20 quarts from a bushel.  Quite a wide range but there you have it.

2.  Equipment and supplies needed are:
Canner (borrow one if you don't have one) and rack.  You can use any big old pot as long you have some kind of a rack that will keep jars off the bottom and there is enough room for 2 inches of water above the jars as well as another 2 inches for space for the water to boil up.
Canning funnel, jar lifter, canning jars (you can use pint or quart), lids, rings, paring knife, measuring spoons, cutting board, pot for boiling water for blanching tomatoes (to skin them), slotted spoon or strainer to lift hot tomatoes out of blanching water, four bowls - one for hot tomatoes pre-peeling, one for peeled tomatoes and one for peels and cores,  a sauce pan for holding rings and lids in hot water,  dish cloth and towels for wiping up, citric acid, salt(optional)

3.  Wash jars, lids and rings well in hot soapy water.  Rinse well.  I turn jars upside down on a clean towel until I am ready to fill them.  Hold rings and lids in simmering - not boiling - water.

4.  Fill canner about half full with warm water and start heating.  (You may need to add more hot water later - Once the jars are lowered into the canner there needs to be about 2 inches of water above the tops.)

5.  Prepare tomatoes.  Wash and remove stems.  Place a few tomatoes at a time in a pot of boiling water for about 2 minutes - watch for skins to crack a little.  Remove tomatoes and place in a bowl of cold water to cool so you can handle them.   Peel and core tomatoes.  Put skins and cores in your compost.  Put peeled tomatoes in a separate bowl.  It is most efficient to prepare all the tomatoes you are going to need at once.  Unless you have more than one canner, you probably shouldn't do more than 21 pounds at a time.  You can start all over again when the first batch is being processed.

6.  Add 1/2 t. citric acid to each quart jar and salt if desired - 1/2 to 1 t. per quart.  If you are using pints, reduce salt and citric acid by half.  You can substitute 2 T. bottled lemon juice per quart of tomatoes for the citric acid.  The citric acid/lemon juice is important.  A water bath canning process is safe only with high acid foods.  This guarantees that the acid level will be high enough and your tomatoes will be safe to eat.  The salt is for taste - not for preservation or safety.

7. Using the canning funnel, pack each jar with raw tomatoes.  Press down firmly - because tomatoes will shrink during processing.  Use a chopstick or other non metallic tool to remove air bubbles - slide down the side of the jar.  Make sure to leave 1/2 inch head space - the distance between the top of the tomatoes and the top of the jar.

8.  Wipe jar rims with clean cloth or paper towel.  Place lids and rings on jar and close - but not too tight.  As soon as you feel resistance, add another quarter turn.  You want the air still left in the jar to be able to escape during processing.

9.  Place jars on rack and lower into the water in the canner.  The water should be hot but not simmering if you are doing a raw pack.  Add boiling water if necessary to bring level 1 or 2 inches above the jars.  Do not pour boiling water directly on the jars.  Cover the canner.

9.  When water comes to a full rolling boil, start counting processing time. Boil gently and steadily for the time recommended  - which in the case of raw pack tomatoes is 85 minutes for altitudes of 1,000 feet or less.  I think most of Minnesota is in this category. Minneapolis is 837 feet.  (Note - altitude matters.  Canning guides will tell you what time to use for your altitude. )

Note on processing time.  I have been canning raw pack tomatoes for a long time and have never processed them for more than 45 minutes.  I must have missed the big news when the canning gods decided to change it to 85 minutes.  I will change my ways but I am looking forward to finding out why this recommendation changed so much.

10.  Carefully remove jars from the canner with a jar lifter.  (if you have a rack that "hooks" onto the canner - lift that up first) Place jars on a dry folded towel or other surface that is not cold.  (the jars might break)  Cool, untouched, away from drafts.  If you hear little popping sounds, smile.  That is just the lids sealing.

11.  Next day.  Test each jar for sealing.  Put your finger on the middle of the lid and press.  It should not move up and down - it should stay in a slightly concave state.  Remove rings.  Wipe down the jars with a damp cloth.  Label with date and contents.  Store in a cool dry place.  If a jar doesn't seal, refrigerate and use it up.  Or freeze it or recan it (repeat the whole process).

1 comment:

  1. The canning posts were so great, Peggy. The posts made me really want to try canning. I think that this year though I'm going to take your advice and achieve the goal of learning to cook and eat the veggies in our CSA. This was an ambitious project for my fiance and I. That and the worms. We got our worms for our vermicomposter last week. We named them all Bob. We have a pound of Bobs in our composter in our condo's garage. Great air circulation and temp control so they love it. I hope. They have started eating so I take that as a good sign. Anyway, Next year I'll try canning and refer back to this post.