Putting Food By - Janet Greene [59]
The federal, state, and non-government experts whom PFB has consulted since the “great tomato revolution” of 1974 agree 100 percent that clean, careful handling, and due respect for the Whys of good packing and processing, are the primary safeguards in canning tomatoes of all varieties.
Selecting the fruit. Use only firm-ripe, unblemished tomatoes, ones that have not quite reached the table-ready stage wanted for slicing and serving raw.
Discard any that have rotten spots or mold. (The regulations governing commercial canning regard just one decomposed tomato per 100 sound fruit as reason enough to condemn the entire lot as unfit for human consumption.)
Discard any that have open lesions.
Washing. Wash the fruit carefully in fresh water of drinking quality. If many are spattered with field dirt, or have not been staked or mulched in your own garden, add a little mild detergent and 4 teaspoons of 5 percent chlorine bleach to each 1 gallon of wash water; rinse well in fresh water. (This thoroughness cuts down bacterial load.)
Peeling and cutting. You will be working with clean equipment and cutting surfaces—just as you do when handling any food you’re putting by. Peel tomatoes by dipping a few at a time in briskly boiling water, then dunking immediately in cold, clean water: the skins will strip off.
Without cutting into the seed cavity, ream out the stem end and core (the point of an apple-corer does a good job). Cut off the blossom end. Cut off any green shoulders to ensure a product of uniform tenderness and flavor. Cut out any bruises, no matter how small.
Cut/chop as individual instructions say to.
Packing. Pack in clean, scalded containers. All tomato products are packed Hot, with the contents of cans exhausted to a minimum of 170 F/ 77 C if the tomatoes have cooled after precooking. Add acid and optional salt. ADDING ACID IS NOT A CRUTCH. Increasing acidity does not allow you to shortcut any step in safe canning procedures.
Processing. Whether you process in a Boiling–Water Bath or in a Pressure Canner, time the processing accurately: from return to the full boil in a B–W Bath; or after 10 pounds is reached, following a 7-to-10-minute strong flow of steam from the vent (depending on the size of the canner) to ensure adequate pressure inside.
Removing and cooling containers. Follow instructions given toward the end of Chapter 6. Complete the seals on bail-type jar lids as you take them from the canner. NEVER RE-TIGHTEN TWO-PIECE SCREWBAND LIDS. AT ANY TIME. EVER.
Remember that hastening the cooling of jars can cause them to break; retarding the natural cooling of jars can cause thermophilic spoilage (like “flat sour”) to develop in the contents. But cool cans quickly.
Check, clean, label and store containers according to Post-Processing Jobs in Chapter 6.
CONVERSIONS FOR CANNING TOMATOES
Do look at the conversions for metrics, with their workable roundings-off, and for altitude—both in Chapter 3—and apply them.
The Choice Between Processing Methods
Until the extensive research on lower-acid tomatoes is completed and the reports are correlated, there can be no consensus that says tomatoes must be Pressure-processed to ensure a safe home-canned food. In the meantime, each householder must make a judgment call.
If you have reason to think your tomatoes are not quite within the acid range for the B–W Bath (a pH rating more than 4.6, or even the 4.7 cutoff some experts sanction)—because of the way they were grown, or if you’re stuck with fruit that’s past its ideal condition—then just let informed good sense choose between:
Either (1) increasing the acid content of the pack yourself (how, is told below), and use a proper B–W Bath (212 F/100 C) for the time specified.
Or (2) processing at 5 or 10 pounds pressure (228 F/109 C, or 240 F/ 116 C) for the length of time given for the individual tomato products.