PRESERVING PROBLEMS

New Zealand Listener, Volume 18, Issue 452, 20 February 1948, Page 26

PRESERVING PROBLEMS

Chain have written to me about their difficulties in preserying fruit. The whole trouble seems to be in getting a perfectly airtight seal. The infuriating part is that although one seems to follow exactly the same procedure every time, and ‘to carry out the directions exactly, yet sometimes the seal will be perfect and sometimes it won’t! This is especially the case with the new two-piece metal caps, which have replaced the rubber rings and screw-tops which we used to have before the war. Actually I think there was just as much trouble with the old lids-people had occasional failures just the same, judging by my mailS Links in our Daisy bag of those days; and the younger "housewives, having never known any but these two-piece caps, start off without any prejudice. Typical Problem Here is a typical problem received this year; "I preserved a lot of plums and other early fruit, using the twopiece vacuum tops. Last year I was quite successful with these, but this year nearly all the seals have come loose after two or three days. I put the fruit in hot, and did everything the same as I did last year." Well, of course, there was a loss of vacuum somehow or other. You seem to have used the second method described on the replacement lids-the method whereby you cook the fruit in syrup first, in a pan, and then transfer it to the hot jars. I think the fruit must have lost some heat in the transferring process, and before you sealed the jars. This would cause loss of vacuum, even though it may not have been apparent for a day or two; or else you did not . screw down the outer lid tightly enough, In both these cases, the result would be a slight introduction of air, which would allow mould to grow. The whole point is that the process is a vacuum one, and so the greatest heat commensurate with safety must be obtained, so that the greatest degree of vacuum is obtained on cooling. On the other hand, you may have had a faulty cap, or jar. In the first method described on the replacement lids, you fill the heated jars with fruit and boiling syrup-or water leaving a half-inch space at the top, or one inch in big jars. Then the inner cap is put on, being careful to see that it is a good fit (sometimes they are too large for the jar!) and also being very careful that the top of the jar is wiped quite clean as well as the inner lid. The slightest bit of food or even of syrup may spoil the close fit. Also run a knife round the inside of the jar to get out any air bubbles, Another point to watch is to screw down the outer lid tightly. The directions say "not a vice-like grip," but nevertheless it must be screwed hand-tight. I myself have had the inner lid come off when I removed the outer screw-lid because I had not screwed it down tightly enough; and so, when the contents cooled, some air sucked in and spoiled the seal, Another point to watch iis that the fruit must be processed

at boiling point for at least 20 minutes, so that all the air is driven out, Also be sure that the syrup in the jar does not actually boil, or it may bubble up against the lid and spoil the seal. When the inner caps are tight at first, but loosen after two or three days, it may be due to a faulty cap, or jar; or else the jar has not been processed long enough, so that the fruit is not completely sterilized and gas has cole lected. Summary: 1, Do not use jars which have the slightest imperfection or chip around top edge. 2. Fill jars to within one inch of top with raw fruit and boiling syrup. 3. Wipe both top of jar and screw lid carefully. 4, Fit on the inner lid and screw the outer cap down firmly. 5. Process in water-bath for 20 to 30 minutes at least. Tomatoes and pears should be, left longer, 6. Have the water in the sterilizing vessel up to the neck of the jars, and see that it boils fast and steadily. Otherwise the fruit in the middle of the jar may not be heated long enough, and to a high enough temperature, to effect complete sterilization and to cause a strong vacuum to form. 7. Take out jars very gently and stand upright on a wooden sur4 face, not in a draught. Do not bump or jolt the jars. 8. Leave for 24 hours, 9, Unscrew the outer cap. The inner lid should be firmly held on, and should give a ringing sound when tapped with a spoon. It may be sucked in to be slightly concave, The fruit has generally risen in the bottle. If you find that the igner lid is loose, and a vacuum has not formed, just take off the inner lid, cleanse it thoroughly, replace it, screw it down, and reprocess as before. Leave 24 hours again. 10. Both methods printed on the inner lid are good. The first method is perhaps the surest, because by it the fruit is cooked in the jar and the maximum heat is generated. The jar must never be turned upside down to cool; and after 24 hours the outer screw band should be loose, and quite easily removed. The fact of the outer screw band being loose, after having been tightened down initially, shows that the vacuum has pulled the inner-lig down firmly on the rim of the jar, A good test is to tap the inner lid with the fingernail, when a clear ringing sound should result. It is necessary to remove the outer cap to find out whether the inner lid ig held down firmly by vacuum. Also, if not removed, it may corrode on the side of the jar and after a time may be impossible to take off without destroying. These screw bands may be used many times; but the inner caps only once, be(continued on next page)

(continued from previous page) cause to use the fruit you must puncture the lid with a sharp point, in order to relieve the vacuum and allow the cap to be taken off easily. It is not wise to try to prise the lid off without puncturing; and never use the inner caps again. Sealing Odd Jars I am at present testing a new English seal, which may be on our market next fruit season, This will be most useful because it can be used on any shape or kind or size of jar. It is a kind of

plastic skin, and you cut off the pieces you require, something like cellophane, but much thicker and really different. It is used both for preserving and for jam, and is tied at the mouth of the jar with special string. In processing fruit, the jar must be completely covered with cold water in the sterilizing vessel. During the boiling, the material (which has been drawn over as tight as a drum and tied) billows up like a big bubble! After removing from the water, this bubble is sucked down into as deep a hollow! It is quite easy to use, and can be washed and used again.