Pressure canning

[nun_hunter]

Pressure canning is popular in the USA but seems relatively new here with most supplies and equipment coming from the USA and therefore harder to get and very expensive.

Does anyone here (UK and USA) have experience if this method or preserving food and the pros and cons of doing so.

I eat venison a few days a week all the time but my wife isn't a fan and my boys only really like a rare steak whenever I cook them. At the moment I end up cooking a whole shoulder or similar then freeze into portions but the canning method seems like a different way of preserving individual small portions and not using the freezer to keep them preserved. Also it would make a better method of giving venison away in a prepped format or taking it when I visit friends/family and not worrying about it defrosting.

 

[Paul 600]

Have a look at using screw top mason jars and a cheap vac packer with a home made pvc pipe chamber. Very popular stateside.

 

[nun_hunter]

Have a look at using screw top mason jars and a cheap vac packer with a home made pvc pipe chamber. Very popular stateside.

I'd still need something to boil them in first in a decent batch and not sure I'd get the temp high enough without the pressure to ensure the food is safe, especially meat.

 

[jthyttin]

My apologies in advance, if terminology is not right.

In several countries in the continent it's quite commonplace to conserve meat / fish / etc. in tin cans.

You don't really need any equipment to approximate it, but I don't think I'd prepare canned meat for everyday use in household. But if you're keen to try you need:

- glass jars with lids that have seal and will take 100C temperature (most if not all glass jar goods from store will give a usable can)
- large enough kettle that takes amount X of the jars (this will be your patch size)
- stove or some other way to keep certain heating power on the kettle for several hours

You basically cut up the meat, season to taste (be careful, flavors might intensify while cooking), add salt (preferably blanded nitride salt, but be sure to check how much you can use it safely). Most would like to add some "jellifying agent" e.g. potato flour to make sure the end result is solid not a combination of meat and liquid. You also want to make sure the fat content is adequate but not excessive. Stuff the mixture in the jars, try to get the air out from the mixture. Leave at least 1cm "neck" i.e. don't fill to the brim. Put the jars in kettle, fill with water and heat it to the boil. Watch occasionally and adjust the heat to have gently rolling boil. Add water to keep the jars under water (I find that kettle with lid don't need extra water even if you leave it overnight.

In few hours the jars are ready, but they are not "full conserves". There's a thing called "f value", that describes how long you need to keep then cans / jars in certain temperature to reach certain thresholds. In unpressured kettle you need about 11 hours "hold time" (time begins only after the middle of the jar has reached 100C temperature) to reach f value of 5, that is usually considered to be "full conserve". In pressure cooker, if you can e.g. reach 120C temperature the time is only 8 minutes. Personally I feel that result is better with longer cook time, even with pressure cooker I'd use 105-110C temperature and longer cook time.

You can add e.g. raw potato cubes and root veggies in the mixture, so you have "instant meal in a jar". You can also use oven for the heating, but IMHO the risk of ruining the end result is far greater. In kettle the temperature won't go over 100C so the mixture won't get charred etc.

EDIT: after cooking you should let the jars cool somewhat gently, and observe that the lid is curved inwards when they're cooled. If lid is curving outwards nothing is lost, just eat the contents or put jar in fridge where it will keep for few days (just like you cooked regular food and stored the extra in fridge). You may have to experiment with different jars, and keep note how many times you've used the lids. If there's some damage to jar just bin it. The "consumable component" is the lid, the jar doesn't wear out as long as you don't damage it.

 

[VSS]

As a method of preservation, canning has had occasional peaks of popularity in the UK, but the risk of botulism is generally what puts people off.

 

[NoIDeer]

The very little I know about this has put me off. You need a proper high pressure cooker to get the temperatures. Smart devices like instant pots don't get to high enough pressure. As said the risks of pathogens is high if you get it wrong. I have stuck to canning fruits and the like.

Good luck, do your home work first.

 

[jthyttin]

You need a proper high pressure cooker to get the temperatures. Smart devices like instant pots don't get to high enough pressure.

You only need higher pressures and temperatures if you run a commercial operation or are otherwise trying to minimize time and cost (in my semi-educated guess, it doesn't take too much more to keep pressure cooker at 120C than it takes to keep a kettle at 100C).

I did a quick search already before writing my reply (post #4). Didn't find adequate source in English, probably used wrong search terms. But here's a page in Finnish, the bottom half of page is a table where you can see how many minutes "hold time" you need in specific temperatures to reach f value 5, 7 and 10. I find the values reliable, they coincide with other sources I've read.

Painekeitinohje - Erätapio

Painekeitinohje Lämmön siirtymiseen eli siihen, kuinka nopeasti lämpötila säilyketölkin keskipisteessä nousee halutulle tasolle (114–120 °C), vaikuttavat seuraavat seikat: F-arvo Elintarviketeollisuudessa käytetään kuumennuskäsittelyn tehon yksikkönä ns. F-arvoa. F-arvo 1 vastaa 1 minuutin...

www.eratapio.fi

 

[nun_hunter]

As a method of preservation, canning has had occasional peaks of popularity in the UK, but the risk of botulism is generally what puts people off.

Which is why I presume the proper pressure canners are quite expensive and come with plenty of instructions. The US versions come with a lengthy FDA booklet on what is required to remain safe.

From the reading I have done using a proper canning pressure cooker with correct jars and lids is pretty safe. Just boiling some jars in a pot on the stove maybe not so much.

 

[jthyttin]

Boiling will destroy the botulism toxic, and using nitrite salt (sodium nitrite, curing salt, pink curing salt, ...) if there are surviving spores it will inhibit them from growing and creating more toxin.

But too much nitrite is deemed to be harmful, so you should consider the total intake i.e. how much you put in products and how often you use them. And pure sodium nitrite is toxic, so ideally you want to use a product where sodium nitrite is blanded with sodium chloride (maybe 4% nitrite to 96% chlorite). Or if you use pure sodium nitrite you should mix it with water and make sure it distributes evenly.

If you want to use pressure cooker alone to destroy the spores, you need to go "full monty" and reach honest 121.1C for 3 minutes, and even then it's a probability calculation not mathematical certainty. Good news is that few more minutes and your jarred/canned/conserved goods are ready.