Pressure canner, would you buy this?

[Nomada]

I'm looking at buying a pressure canner (not a cooker) for preserving a lot of allotment produce. I've not space for a large freezer but I do have cupboard space for a lot of bottled foods. The one I'm looking at is a total of £70 including p and p from America. It's a second hand 17 quart presto. Do you think this might be a good deal? It's a lot of money for me to drop at once but I'm doing another teaching job soon that should pay for it with some money left over for kilner jars. Do yuo think it's worth it? I'm looking at it as an investment for the future. Less electricity to bottle the food rather than pay for another freezer then also the electricity for it to freeze a lot of food. Any thoughts? Should I go for it?

[indy]

I have no thoughts other than t say I watched a program about preserving food the other day and they had a segment on it that was very interesting and they looked most useful, I shall follow this with interest to see if anyone else has one as I certainly take your point about not using electricity.

[Green Aura]

I'm not sure you need one. I'm not sure why they use them, unless they're planning on bottling something now for the next millenium I think it's a bit belt and braces - although I'm sure someone will put me right

We put everything in washed, oven-dried (150oC for about 15 mins) kilner jars - filled and closed while jars and contents are still hot. They seal as they cool. I've never had anything go bad yet. Same for jam jars - as they cool the thing on the top pops in. If one doesn't stick it in the fridge and use that one first.

[gregorach]

70 quid including p & p? That looks like a pretty good deal to me, secondhand or not. If you take a look for pressure canners on eBay, you'll find that p & p alone will usually cost about that much.

Pressure canning is for foods with a pH too high to inhibit the growth of Clostridium botulinum (aka botulism - although technically this is the poisoning caused by the toxin it produces), which is an extremely dangerous bacterium - ubiquitous in soil, able to thrive in anaerobic conditions and withstand high temperatures. It cannot be killed by mere boiling, does not cause any obvious signs of spoilage, and it produces one of the most deadly toxins known to man.

Here in the UK, we usually pickle things before bottling them - this lowers the pH and inhibits the growth of c. botulinum (if you do it right). However, for things such as tomatoes which you don't pickle as such, you still need to add enough acid (usually in the form of lemon juice or citric acid) to lower the pH to a safe level. For example, San Marzano tomatoes are a low-acid variety, and should really have some acid added for bottling, or be pressure canned.

Having said all that... Yes, I've bottled tomatoes without adding acid and consumed them several months later without ill effect. However, I'm a strapping fellow in good health. Children and the elderly are more prone to botulism, but at high enough levels, it can kill even the fittest adult. Considering the lengths many on here seem to go to to avoid "artificial" "toxins", how sanguine are you about a well-known and understood form of potentially life-threatening food poisoning, which results in about 110 cases per year in the US, with a case fatality rate of about 4%? Especially when you consider that doctors in the UK are much less familiar with it, since we don't generally do as much home canning here?

[gregorach]

We put everything in washed, oven-dried (150oC for about 15 mins) kilner jars

Fun microbiology fact - genuine sterilisation with dry heat requires 2 hours at 160 C. However, when you're dealing with pressure canning, it's not the jars you're worried about...

[RuthG]

70 quid including p & p? That looks like a pretty good deal to me, secondhand or not. If you take a look for pressure canners on eBay, you'll find that p & p alone will usually cost about that much.

Pressure canning is for foods with a pH too high to inhibit the growth of Clostridium botulinum (aka botulism - although technically this is the poisoning caused by the toxin it produces), which is an extremely dangerous bacterium - ubiquitous in soil, able to thrive in anaerobic conditions and withstand high temperatures. It cannot be killed by mere boiling, does not cause any obvious signs of spoilage, and it produces one of the most deadly toxins known to man.

Here in the UK, we usually pickle things before bottling them - this lowers the pH and inhibits the growth of c. botulinum (if you do it right). However, for things such as tomatoes which you don't pickle as such, you still need to add enough acid (usually in the form of lemon juice or citric acid) to lower the pH to a safe level. For example, San Marzano tomatoes are a low-acid variety, and should really have some acid added for bottling, or be pressure canned.

Having said all that... Yes, I've bottled tomatoes without adding acid and consumed them several months later without ill effect. However, I'm a strapping fellow in good health. Children and the elderly are more prone to botulism, but at high enough levels, it can kill even the fittest adult. Considering the lengths many on here seem to go to to avoid "artificial" "toxins", how sanguine are you about a well-known and understood form of potentially life-threatening food poisoning, which results in about 110 cases per year in the US, with a case fatality rate of about 4%? Especially when you consider that doctors in the UK are much less familiar with it, since we don't generally do as much home canning here?

So are you saying that we should or should not home can? And is a pressure canner a good purchase?

[gregorach]

Home canning is good, as long as you do it right. Whether a pressure canner is a good purchase depends on what you want to can. If you want to can unpickled vegetables (other than tomatoes) or meat (other than confit or similar), I would say doing it without a pressure canner is a bit dicey. If you're only canning properly-made vinegar pickles, it's completely unnecessary. If you're canning tomatoes, you can manage fine without it, but you should probably pay attention to the level of acidity, and think seriously about water-bath canning. If you want to preserve lacto-fermented pickles for long periods, I haven't a clue...

Personally, I'd probably just buy a decent autoclave, but that's because I have other uses for such a beast. I may end up experimenting with pressure canning in my pressure cooker if the tomatoes do well this year... (If I can fit my Kilners in there, that is.)

I should probably point out that this is mostly based on reading rather than direct experience... But botulism is one of those things where direct experience is best avoided.

[RuthG]

Thanks for the clarification. I wasnt sure whether you were saying at first that using a pressure canner increases the risk of botulism. As you say, first hand experience is best avoided! Anyway, I'm clear now, thank you.

[gregorach]

Thanks for the clarification. I wasnt sure whether you were saying at first that using a pressure canner increases the risk of botulism. As you say, first hand experience is best avoided! Anyway, I'm clear now, thank you.

Sorry for the confusion! Just to be absolutely clear: a pressure canner is what you need to prevent botulism in low-acid foods.

The USDA are the definitive source of information on home canning: USDA Complete Guide to Home Canning, 2009 revision. They may seem a bit OTT, and in fact they quite possibly are, but if you follow their guidelines to the letter, you can be sure that your home-canned food is safe. However, do be aware that a US pint is not the same as a British pint...

[Green Aura]

When we do tomatoes we put them in raw with a little salt and sugar, no acid, and cook them in open Kilner jar for about 90mins then put the ring on and shut them straight out of the oven. Seems to work OK.

[gregorach]

Yeah, it's one of those things - you'll almost certainly get away with it (especially if you're a healthy adult), but in those rare cases when you don't, the consequences can be very nasty indeed. Sure, generations of people have mostly managed just fine with such methods, but do you want to risk being the exception?

Like many things, you can get away with a lot, right up until the day you don't.

[boboff]

The botulism is normally soil based, so good washing will stop it.

I think home canning is a bit over the top ( the canning allows the Bot Cook, which is something like core of 123c for 5 mins ( been a few years sorry if a bit out Dunc!)

Ph to inhibit Bot needs to be below 4.2, but it is all open to opinion.

Apertisation in Kilners I think is more than enough, the process I used, which was approved by Campden and Chorleywood was a 4 stage system of in Jar Apertisation. Basically you fill your Jar and seal it, warm it in a 50C tank of water for 10 minutes, then put it in a tank of water at 90c, for anywhere between 30 and 90 minutes, but long enough to get the core to the equivalent of 93.3c for 5 minutes for raw ingredients, 85c for 5 minutes for already cooked product ( like apple sauce say) there were z value and formulas involved for "effective lethal doses" etc. Anyway then into a cooling tank at 50c for 10, and then either an ambient bath or air cooled, depending on how dence the contents, this cooling water was brominated just in case.

My Nan used to just put the jars in a saucepan of water on her Rayburn, and she's been feeding us stingy runner beans for years!


(As it was always NPD we used to establish the timing using dataloggers, probes, and TTI particles etc, with the data put in a spreadsheet I wrote, which produced a graph telling you when you have cooked it long enough, and as the hear was different in different parts of the tank you had to take a worst case approach, it was all very good fun, and extremely interesting I will have you know,,,,,,,.............Yawn,)

Lidl's do a pasturiser / Home "Canner" pan for about £40 in September, it has a thermostat and a timer and alarm etc on it, I would recommend it, the German ones from "Weck" are about three times that price.

[Nomada]

Thanks for the advice, any more opinions appreciated. We'll discuss it some more. There's five of us needing to be fed from the allotment and two of them are children, my friends 10 and 3 year old boys so I know for a fact she wont risk it (botulism). We share the allotment and we've been mulling it over recently. I'm also going to dehydrate a lot of stuff for myself but she doesn't like that so things that I'd dehydrate she'll want to freeze and she doesn't want to use a lot of brine or sugar to preserve things that the kids will eat (my bloke also can't have brine anyway on account of his bad kidneys). She'll eat the likes of onions and beets pickled but nothing else wheras I'm not so fussy. I'm hoping to lacto ferment a lot of stuff anyway. Freezer space is a problem for me more than for her. I personally might consider canning meat and fish in the future in which case I certainly would need one probably, but I'm not 100% sure it's a need right now.

[grahamhobbs]

We do a lot of bottling without a pressure canner, tomatoes and apples. We've tried different methods, wet, dry, oven, etc using make shift equipment. It is not easy (especially in a small kitchen), your saucepan is not tall enough, the oven won't take many jars, etc and having gone through all that some still start to ferment.
In France they do a lot of bottling, including vegetables (can't say its worth it given how they're cooked to smithereens), but they have big canners fitted with temperature gauges, maybe they take a dozen jars. These are efficient, but even better I imagine would be a pressure canner. Firstly it would be quicker and secondly will heat the jars reliably.
I've used a big canner (not a pressure canner) with a thermostat and timer, this was also very good, because you could forget about it and let it bubble away, confident that everything would be cooked properly. But these cost I think £150 new.
So £70 sounds very good.

[MKG]

99 times out of 100 (or even more), I'm going to agree with everyone except Dunc. For that odd one case (and that's the one that kills you) I wholeheartedly agree with Dunc. Especially with tomatoes. Botulism poisoning is rare - but I still wouldn't take the risk. Get that acidity adjusted or buy the pressure canner. £70 sounds cheap to me, and it covers all bases.

Mike