How to minimise waste when making preserves safely and cheaply?

Question

When reusing preserving jars, the most commonly available metal lids (with a rubber or soft plastic seal) are really just meant for a single use. I did find some reusable plastic lids (BPA and pthalate free) through Google, though whether they'd be available in New Zealand where I live, I have no idea (but it's unlikely to be easy to find or affordable).

Are used jam jars or other used jars suitable for preserves? (can the lids be safely boiled, and an airtight seal be obtained reliably?)

Are there any other readily available methods for safe, cost effective preserves that minimise waste?

Answer 1

You can buy lids with seals and a bunch more stuff in NZ, from Mapau Country Trading Company in Nelson or 3BucketsFull for example. I did a search using these terms "buy preserving jar lid with seal nz" to find those results. I would not be surprised to find them in some of the more rural supermarkets as well, but the easy place to start is online.

I grew up in a horticultural area in NZ and we did a lot of preserving because fruit was cheap in season. Mostly we used what the posters above are calling "Mason jars", but the brand names are different in NZ and my extended family didn't refer to them by brand name, just as preserving jars and preserving lids.

For seals I've used wax extensively in the past when we used to make a lot of fruit preserve and it worked well. The main failure mode was content shrinkage pulling the wax down out of the neck of the jar. The solution is to put the wax where the sides are parallel (which limits the jars you can use), and you usually have a fair bit of airspace, but IMO better that waste than spoiled preserves.

If I was starting to collect jars now I would be very tempted by the coffee jars with glass lids and low-quality plastic seals (Moccona is one brand that's available in NZ). Use wax for the real seal, only put the lid on once the jar is cool. But first, get a couple of jars and make sure they will cope with the heat of preserving. The reason for this is that the jars are pretty readily available second hand/free.

Wax, by the way, can be collected and reused with a little effort. Or keep bees and get it free :) Since we had a beekeeper visit us every spring to pollinate fruit we used to buy wax and honey off him at the same time. But we still re-used the wax, either for preserving or in candles. The trick is to use a metal fish slice to cut a little groove into the wax without breaking the seal, invert the jar to tip the wax shavings out, then push down to crack it into two pieces that can be lifted out of the jar whole. That way you don't end up mixing lots of little fragments into the jam (my little sisters preferred the "hulk smash" approach that made the top few centimetres of jam quite waxy).

(I commented above but decided 300 words of comments was enough to make this an answer, so sorry for the duplication).

Answer 2

Scope of Answer and Safety Information (please read)

This answer assumes that "preserves" refer to fruit preserved with sugar. It does not apply to vegetables or meat, or to cases where large amounts of sugar are not added. If canning in those environment, please use more conservative approaches, or better yet from a sustainability perspective use more traditional means of preserving these foods for later, such as sauerkraut and salami.

Fruit is not considered to be a particular risk when canning and if you go back a thousand years or so fruit preserved in sugar was stored open. The acidity and sugar together combine to prevent harmful bacteria from growing, and white sugar is considered, at least by archaeologists, to be better at preserving fruit than honey is (see "Anglo-Saxon Food and Drink" by Ann Hagen).

Additionally there are a few fruit which have fallen out of favor which are traditionally preserved with citrus added, most notably the quince ("marmalade" comes from a word meaning "quince jelly"). If going outside of the common fruit used for such preserves, you may want to test pH (which may be a good idea anyway). If in doubt, add some extra lemon juice or other acidic fruit.

Additionally, even in the Middle Ages, such preserves were cooked, both before bottling and after bottling, so you can't omit the water bath.

For fruit preserves, a pH of 4 gives you extra room in case the pH rises due to any number of factors. Also note that fermented foods generally (that includes either lactic fermented foods like sauerkraut and alcoholic fermented foods like beer) are not botulism risks.

For more on safety, please see:

http://www.hc-sc.gc.ca/fn-an/securit/ill-intox/botu-eng.php

http://www.publichealthgreybruce.on.ca/communicable/fact-sheets/botulism-food-borne.htm

As always, defence in depth is important and canning is a part of that depth today when making fruit preserves.

Main answer

The old traditional method of sealing was to use wax. There's no reason why a "float" of beeswax won't get you where you need to go along with jars which cannot themselves be sealed. While this often works it is not perfect and the seal can break. This being said there isn't any reason why this can't be used as one aspect of a seal. It may not be perfect, but it is simple to do, and if the product is used within a few months, it is likely sufficient.

I would prefer beeswax to paraffin not only for sustainability reasons regarding the material itself but also because beeswax is softer stickier, and less brittle and so I would expect that it would be less likely to come loose.

Another option, as you mention, is to re-use existing jam jars and lids. I have done this with herbal medicine concoctions. This usually works pretty well but some sorts of jars and lids I have learned to avoid not because they won't seal but because sometimes the seals end up locked and the jars impossible to open. Jars to avoid include baby food jars. I would assume that other similar jars should be avoided too. Note you can test a seal with these by virtue of the fact that the button pops down. If this doesn't happen, try a wax seal on these, and use first.

Answer 3

I used jam jars without rubber seals, with success (meaning the goods kept) for vegetable bases pastes. The pastes were put into tha jar cooking, after cooling you could hear a "pop" when opening, meaning the seal was adequate. To find out if your local jam jars are ok without a rubber seal, consider putting some boiling water into the jar, close it, wait for it to cool, and listen if you hear the "pop" when opening.

Answer 4

Used jam jars work fine for me. Depending on what you plan on preserving (and how strongly you preserve it), used jam jars can get you quite far.

There are several factors to consider.

1. How clean is the jar?
   
2. How hot is the preserve at the time of filling?
3. How resistant is your recipe against moulds?

For jams, you can strike a good balance with a 50:50 recipe (half sugar, half fruit). If you fill it still "boiling" the jam will be hotter than 100°C and then it is usually enough to wash the jar by hand and let it dry. (Jams I made this way easily last 2 years.) If your recipe is weaker (only hot fruit @80°C) you will probably want to sterilize your jars (and sort out any jars that smell or look dubious). (E.g. by putting your glasses in a steamer and steaming for 30 min.) And don't use damaged lids!

Good jam jars have a good rubber seal in their lid. Cheap jam jars use cheap rubber seals and are thus less suited. The Weck jars (picture) have again become popular in Europe and Japan and are well-suited for reusing. If you are serious about making preserves every year, you might want to invest in glasses. The rubber seals should officially be changed every time, but tend to last much longer than that. You can use them for storing leftovers as well. They are much easier to wash than commercial jam jars, because they don't have a screwing mechanism and many of them have a straight "neck". (Which makes them less suitable for transporting in cardboard boxes.)