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High Acid, Low Acid, Waterbath or Pressure Can? The Fundamental Decision of Canning

It’s been a very busy week – we’ve had a wedding, family in from all over the world, an accidental dinner parts for more than 60 (we figured we’d get 13), and just an all-out fun party for 3 days.  Connection to the blog and the community here has been very low (a massive pile of comments to go through awaits for a free moment).

We’ve only been around enough to pop by and smile at the messages we’re seeing here and the Facebook Community.  The group was abuzz last night with items that each of us had cooked and were very happy with over the weekend.  Lynne mentioned that she did her first ever batch of canning on the weekend (strawberry jam – this was also my ‘gateway’ into preserving) and that she had fabulous success.

Lynne also mentioned that she had some minor confusion around acid levels and waterbath vs. pressure can.  I think most of us have had this question (I remeber it feeling like such a mystery) as we learned and I wanted to flip her the easy explanation – and realized I didn’t have a short article that explained the differences.  I’m hoping today builds that resource to help those who are learning (and I hope they take comfort that we’ve all tried to untangle this one).  It’s going to be a simplification of the science – so my excuses to the chemists amongst us!

Let’s start with acidity.  Most canning relies on techniques which kill or suspend the growth of yeasts, mould and bacteria.  Acid naturally inhibits many of the nasties so food which is deemed to have high acidity don’t need the amount of processing that non-acidic food does.  Acid is measure by pH level from 0-14.  Pure water is neutral at 7, acidic substances are closer to 0 and base (alkaline) elements increase upwards from 7.

Food which is under pH level 4.6 is considered to be high acid.  This includes almost all fruit and almost no vegetables (tomatoes are close to this ‘magic number’ and it is recommended that you add citric acid or lemon juice to them to increase their acidity). 

High-acid foods are safe to be water-bathed, however:

  • Use tested recipes.  A strawberry is high acid but if you added 3 pieces of bacon for every strawberry, you’re concoction is no-longer high-acid.  Of course this is in exaggeration but it helps demonstrate the point.  And I have seen some recipes online which tell you that you can preserve bacon jam via waterbath which is (as far as I can tell) some very poor advice, in part due to the lack of acidity.
  • When in doubt, check with the pros.  My most trusted resource is the National Center for Home Food Preservation (we describe them here and include a link to them in that article).

You do not need to pressure can high-acid foods.

This brings us to low-acid foods – i.e. most vegetables.  There are two options with them (we’re ignoring other preserving methods like freezing, infusing, dehydrating and lacto-fermentation for now):

  1. Increase the acidity
  2. Pressure can them

Option 1 simply means that we add acid – in the case of tomatoes a small amount of citric acid or lemon juice (as explained at the National Center for Home Food Preservation above) is the most common fix which vegetables like cucumbers become pickles and are submerged in vinegar.  These are then water-bathed – the advantages being that they keep their texture better and you need less equipment than pressure canning – the main disadvantage (also an advantage) is that the taste is transformed to a pickle and not the original vegetable.

Pressure canning allows you to use pressure and steam to increase the heat of the processing while canning.  This attacks the nasties we mentioned earlier.  Pressure canning allows you to preserve vegetables and other low-acid foods (including stocks and meats) so that you can extend your summer food (especially local) through the year.

Rather than repeating a lot of what we’ve said in the past, here’s a few links to start/ help get your head around pressure canning:

To conclude;

  • High-Acid (most fruit) -> safe for all methods.
  • Low-Acid (most vegetables and meat) -> add acid OR pressure can
  • For both -> use tested recipes.

Hope that helps!

We love your questions and ideas (here and at the Facebook Community) – they help us know what you want to know and make for easy topic ideas (something that gets more difficult after every post :) ).

Happy Monday all.

The ‘Secret’ Benefit of Pressure Canning

We’ve written a reasonable amount about pressure canning in recent weeks (expect even more this summer as I anticipate significantly increasing the amount of it that we do) but sometimes it’s so easy to miss the obvious.

If you’re looking to get caught up, here’s a few key posts on the topic:

Pressure caning allows us to preserve low-acid foods (almost all vegetables) without turning them into pickles (and without consuming the limited space in my tiny freezer).  We buy the produce in the peak season (when it is at the rare intersection of superior quality and cheapest price) and store it away packed in lightly salted (an option) water.  The canner brings the heat up to a high enough temperature that the food is safely preserved for a long time to come (we are eating beans that are 18-months old this week).

I generally considered my final product to be the vegetable itself – and often discarded the liquid down the drain.  This meant that I was enjoying the awesome flavor of the vegetable year-round and essentially throwing away vegetable stock.  Yes, the ‘secret’ is that the water you preserve vegetables in is very, very usable.

I’ve thought about freezing the stock in a big ziplock bag until I worked up enough for a pan of soup.  The truth is that it’ll never last that long.  I’m often using it in the same meal – here’s a few examples:

  • We had stir-fried rice with peas.  The water from the peas was used as part of the water to cook the rice in.
  • I warmed Romano beans in their own broth – the broth was later added to a pasta sauce and added a depth that would have been otherwise lacking.
  • Broth from jarred tomatoes (not pressure canned) was added to the bottom of a Shepard’s Pie to stop it from drying.
  • I re-hydrated homemade celery salt, mushroom powder and dried parsley in the water used to preserved long beans.  The resulting ‘paste’ was super-flavored vegetable gunk which was used in a pasta (and could easily hide multiple portions of veggies for kids who are shy of them).
  • The liquid can also be added to polenta which I am still ridiculously addicted to.

These are just some simple examples – the point being is that it’s very easy to find a use to this ‘vegetable tea’ and another example of getting more out of less in the kitchen.

Any other secrets on how to extend ingredients in your kitchens out there (they don’t have to include pressure canning)?  Is there something you used to waste and now find as a useful ingredient in the kitchen?  We’d love you to share. :)

Making and Canning Stock – Part 3 – Pressure Canning (Preserving)

This post may be somewhat anti-climactic.  The most important parts of it are links to a few previous articles because a lot of it is covered there.  I’ll risk the redundancy to share the mysteries of pressure canning because:

  • It’s a natural evolution from water-bath canning.
  • It’s nowhere near as difficult as it may seem – though it can be very intimidating.
  • It’s an essential technique for preserving low acid foods – i.e. most anything other than fruit, most vegetables and pickles.
  • It’s my party and I can if I want to.  (Yes there was a pun on ‘can’ there…) Read more

Making and Canning Stock – Part 2 – Cooking, Cooling, Cooking, Cooling…

Cooking stock is all about patience.  For many years I just through water in a pot of `stuff`and boiled it as hard as it would go and hope for the best.  I`ve learned that`s a bit like trying to build a house of cards with a hammer and nails – it`s a little too harsh.

Our stock is started by adding roasted bones (if you choose) and the roasted vegetables (we also put our burned onions into the mix at this point) into the pot and covering with cool water.

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Making and Canning Stock – Part 1

There was a good deal of discussion around stock when we posted about intentionally burning onions for that purpose last week so I decided it would be prudent to share our process of making and preserving (via pressure canning) stock.

Stock is a winter activity for us.  It can take a lot of time (although much of the time is passive), generate a reasonable amount of heat, and I tend to use it a lot more in the winter.  We generally use 1-2 liters of stock (often more) per week in the middle of winter.  It`s primary uses are soups and stews but it`s not uncommon for a few tablespoons to deglaze my pans or to bring a stir fry together.

The example we`re going to use here happens to be from venison though it would work with any core ingredients – including a veggie version.  I have been saving some of my peelings, carrot ends, discarded onions, etc in the freezer and tend to make a veggie stock on the fly – it is the only stock I make that can be done in a single day (we`ll share more about that later).

If you`re new around these parts and are curious (or even turned off) by the idea of hunting, I encourage you to visit my diary entries from the last 2 years of the harvest.  There`s no gruesome photos and they try to explain a balanced perspective which include my own struggle with a tradition that has lasted hundreds of years through my family. Read more

Pressure Canning Peas and Beans (Preserving Summer)

Like many people, my personal interest in preserving started with jams.  Our pantry is home to more than a dozen types of our own making while it is also home to another few dozen jars that were gifted, traded or purchased.  Jam is a lot of fun to make though my relationship with it is strained as I rarely eat breakfast (my bad).

From jam we progressed to tomato sauce.  The age-old argument that a tomato is a fruit is what makes this a fairly easy transition (more on tomato sauce this week).

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Pressure Canned Asparagus

It`s time for the Tigress Can Jam and the rules are clear: thou shalt use a boiling water bath.

I am a rule bender – but not a complete rule breaker.  So I did indeed make something that was done in a hot water bath.  This just isn`t the post on it (that will come tomorrow).  I did want to take a moment and share a bit about pressure canning with hopes to inspire some of the other can jammers who haven`t tried it to give it a go.

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Final Preserving batch of the year – Turkey Stock

We live in an apartment in Toronto – while we are fortunate to have lots of space inside our walls, very little of that is freezer space.  My entire freezer consists of the small chest above our fridge and some borrowed space in Markham (about a 30 minute drive from here).  This is part of the reason we can so much.

As we cook fairly often at home, I keep a jar of stock open at almost all times.  Stock is just a handy staple and something that`s tough to live without.  We use it in soup, pasta, to de-glaze pans, stirfrys, cooking rice, steaming anything and so forth.

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