Mason Jars Are All the Rage But Here's Why You Should NEVER Cook in One

Using jars as bakeware might be a shattering experience.

Mason Jars Are All the Rage But Here's Why You Should NEVER Cook in One

Is it safe to bake in a mason jar? The answer is: no. Here's why.

Canning jars are built to be durable, but many people make the mistake of thinking that because they're glass, they're oven-proof... just like Pyrex. 

They're not the same thing. 

Glass expands when heated, like many materials. When it cools, it contracts. Objects that are heating or cooling usually do so unevenly due to a number of factors, including what may be touching it or even just the flow of air around it. But what many people don't know is that this causes the material stress.

To some degree, glass can handle the stress placed on it by heating and cooling, as long as it doesn't happen too rapidly and from extreme hot (such as an oven) or cold (like a freezer). Your glassware doesn't usually break when it comes out of the dishwasher and finishes cooling down in the cupboard... but it will, if you take it fresh out of the dishwasher and put it under the tap for a cold drink. Cracking from the sudden temperature change is called thermal shock.

But there are different types of glass, and different types of glass have different strengths. The different strengths come from how the glass was made and what it was made from.

Pyrex, which is oven-safe, is made of tempered glass--also known as safety glass. But even Pyrex has its limitations, and it is still vulnerable to thermal shock. If you've ever set a hot Pyrex dish on a cold surface, you may have had to duck for cover. Like all safety glass, in conditions that cause it to break, it shatters explosively into many small, blunter - mostly harmless - fragments, designed to help protect you from getting cut badly.

Mason jars are commonly made of annealed glass. When annealed glass fractures, it will shatter into irregular, very sharp pieces and miniature shards. This can cause you minor injury if you're holding it at the time, or it can crack small fragments of glass into your food. You should discard any food or drinks contained in a glass in which a crack has formed. When you use mason jars for canning, you should never pour hot food into a cool jar. If you've used a mason to store foods in the freezer, you should also be careful about defrosting them too quickly by putting them under a hot tap or in a pot of hot water.

This Smart Jar Tip Left The Whole YMC Staff Wishing We Had Thought Of It First

But the reason why ovens are an exceptionally bad place to put mason jars is that the temperatures can fluctuate up and down rapidly enough to put repeated thermal stress on the jar. This can happen simply when the oven's heating element cycles itself on and off (as it does once it's reached its set temperature). Opening the oven door and removing them from the oven is another high-stress situation for the jars, as is transferring them to a rack where they can cool down. Foodsafety.gov also recommends that all foods cooked to a temperature over 90F be refrigerated within an hour, which means that you may run the risk of shattering a hot jar by transferring it to the cool environment of the fridge.  

The worst risks, however, aren't simply cracking the glass.

Some recipes recommend baking it with the lid on or instructing you to close the jar shortly after removing it from the oven (such as oven-canning). In both situations, steam under pressure coupled with thermal shock can be explosive, causing burns and sending very sharp pieces of glass flying. And even worse, your risks of cultivating food borne illnesses from this method of preservation are very high. 

An oven is not likely to get the center of your jar hot enough for long enough to eliminate microorganisms for long-term storage on the shelf or in the fridge. Many of these recipes are unlikely to have the correct pH balance to hinder harmful bacteria such as botulism from proliferating, and botulism can kill. If you see "oven-canning" mentioned anywhere on the recipe? Run the other way!

Reconsider using glass in high-stress situations! My recommendation, as it is on Bernadin's and Ball's site? Don't put your mason jars in the oven. 


RELATED: ​Mason Jar Magic: Unique Ways To Use Mason Jars For Entertaining


8 Kitchen Cleaning Hacks That Are Going to Save Your Sanity

Nobody likes to clean or stink. So do this.

8 Kitchen Cleaning Hacks That Are Going to Save Your Sanity

I hate housework

Is the sink gross and brown-stained? You could scrub, or you can use this.

Step 1: Plug sink.

Step 2: Fill sink with hot water and a generous splash of bleach (I don't measure, but it's gotta be a half a cup or so).

Step 3: Ignore for about 20 minutes, or until all the stains are gone and your sink is SUPER shiny! Make sure you rinse the sink well when you drain it.

Bonus: your sink is now sanitized too. AND OH EM GEE, THE SHINY!!!



Serving sticky, gross finger foods? Serve a finger bowl too.

Correct me if I'm wrong, but you don't want it on your walls, yes? Nachos, ribs, BBQ chicken stuff, spaghetti sauce... all bow before the power of the finger bowl. Wet naps suck. Do this instead. 

What is this black magic called a finger bowl? It's a small dish of water with a small piece of lemon squeezed in it. Bonus: kids, especially toddlers, LOVE TO USE IT.

Come on, when do kids ever love to wash their hands? Never. And if they tip the bowl? Big deal. It's a little water with lemon in it. 


Gross cast iron? Scour with this:

To clean burned stuff or built up gunk on your cast iron without wreaking the seasoning and ending up with a rusty pan, use coarse salt and a good-quality food oil to scour the pan. Don't use water, and NEVER use soap. 

Rub the salt against the offending grime until the salt dissolves. Wipe out with a (dry) paper towel. Repeat if necessary.

It's all edible and won't funkify your food, so no water is necessary. If you've wrecked the seasoning on your pan, like hardcore, this can also be used as the precursor to salvage and re-season your pan. Check out my cast-iron first aid for more info on reseasoning.


Love garlic and onions? Hate to smell like them for three days?

Salt and olive oil aren't just for cast iron. They're like stink-be-gone. 

Scour your hands briefly, especially your fingertips, with a pinch of coarse salt and a little olive oil before you wash with soap.

Stink magically goes away.


Does cleaning cooked-on grease off your gas range make you batty?

I love my gas stove. I don't love that spilled oil builds up into a sticky, nasty ring around the base of the burners over time, especially around my 17,000 BTU power burner. Seriously, I get why people opt for glass-top stuff sometimes, cause that sort of polymerized mess never happens with those. But gas stoves are awesome.

DON'T use an S.O.S. pad unless you want to destroy your stovetop.

Use the power trio. It's just like the three-guitar-powered awesomeness of the 80s, only this is the superhero for cleaning caked, rubbery grease. Fill a Scotch-Brite wand with your dish soap. Pour a small puddle of white vinegar on the stove and start scrubbing. You shouldn't have to scrub too terribly hard, cause vinegar and dish soap work like a dragon-slayer on the worst, foulest baked-on messes you can imagine. Trust me, I've spent years trying to figure out what works best. This is it.

Wipe everything off with a damp washcloth when done.


Oh and if you do have a glass top stove and/or want to clean the inside of it, Gwen's got you covered:

Clean Your Glass-top Stove Using Natural Ingredients

Clean Your Oven Door with 3 Things You Have Now


Stinky/Greasy Dishwasher? This might help.

If your dishwasher seems to be making things more dirty than clean, or it has that special, funky odour, run an empty hot load with white vinegar. Feel free to interrupt your next couple rinse cycles and pour in some vinegar too. If the problem is a filter clogged with grease, this might help break it down.

But do realize you're merely prolonging the inevitable and will have to get in there at some point, especially if there's other stuff trapped.


Gross microwave? Make tea first.

Boiling a cup of water in the microwave before you wipe it out will do amazing things for the grease and your blood pressure both.

Throw a teabag in when you take the cup out. You'll be done by the time the tea is.


Hearty Potato Cheeseburger Soup

Wars have been fought over less

Hearty Potato Cheeseburger Soup

This hearty cheeseburger potato soup can be made with aged cheddar cheese or spicy Monterrey Jack for a fast, hot, and filling winter meal! And it's got lots of hidden veggies in it, too. | FoodRetro.com | YMCFood | YummyMummyClub.ca

My husband's not a big fan of soup, generally speaking, but there are two soups I make that have sparked minor territorial skirmishes.

This is one of them.

You see, I like to make meals ahead, pre-portion them and put them in the fridge, so less cooking has to be done on a day-to-day basis.  While he could give no f-words if the soup that I have stored in the fridge is chicken soup, the moment that one of the soups is potato, he gets all territorial. And if you take the last one, he will go all Liam Neeson. 

This hearty cheeseburger potato soup can be made with aged cheddar cheese or spicy Monterrey Jack for a fast, hot, and filling winter meal! And it's got lots of hidden veggies in it, too. | FoodRetro.com | YMCFood | YummyMummyClub.ca

So much for equal partnership in marriage, eh? Fortunately, I know the places in the fridge that my husband never looks, and I hide myself a few servings.

This hot, filling soup whips together in about 45 minutes to an hour for the busy household, and makes plenty of leftovers. You can use practically any cheese you like, though I prefer sharp cheddar or spicy jalapeno Monterey Jack. I've started coming around to using unsweetened, condensed milk in the place of roux to thicken cream soups. Using the condensed milk makes the recipe gluten free and decreases added fat and salt.

It's also a lot easier for people who aren't comfortable in mixing up roux.

Two Potato Soup

Ever since my six year-old and I had a throw down over the importance of aromatics in soup, I've started grinding my mirepoix vegetables (carrots, celery & onion) in soups to puree in advance so that there are no chunks of celery or onion for him to quibble over. If he doesn't see them, he doesn't ask. The other upside to this is there's no soggy chunks of anything, and it helps thicken the soup. You don't have to have a fancy food processor or an immersion blender; all you really need is a little two cup chopper appliance, and I think I bought mine for something like $20 at Sears. If you prefer a chunky vegetable soup, by all means, leave them whole!

This hearty cheeseburger potato soup can be made with aged cheddar cheese or spicy Monterrey Jack for a fast, hot, and filling winter meal! And it's got lots of hidden veggies in it, too. | FoodRetro.com | YMCFood | YummyMummyClub.ca

Serve hot and topped with a pinch of cheese and fried onions, if you like. Either way, you won't find that the leftovers hang around very long.

Hearty Potato Cheeseburger Soup with Spicy Monterey Jack Cheese



  • 1 LB (~450g) lean ground beef
  • 1 medium white onion
  • 2 stalks celery
  • 2 carrots
  • 2 cloves garlic
  • 1 yellow bell pepper
  • 6 cups cubed potatoes (about 5 medium)
  • 1 box (900ml) chicken broth
  • 1 bay leaf
  • 1 tsp dried Italian seasoning
  • 1/2 tsp dried thyme
  • 1/4 tsp ground black pepper
  • 1 can unsweetened, condensed milk
  • 1+ cup shredded Jalapeno Monterey Jack Cheese, plus more to serve
  • Fried onions as garnish (optional), salt to taste


 In a large soup pot, begin to brown the ground beef with a drizzle of olive oil on medium-high heat.

 While the ground beef browns, coarse-cut the onion, celery, carrots and pepper. Smash and peel the garlic cloves, and puree the vegetables into a thick slurry.

 When the beef is cooked, transfer to a colander over a bowl to drain the grease. Dispose of the hot grease safely.

 Return the ground beef to the pot with the vegetable slurry and cook, stirring occasionally, for about 5 minutes, until everything begins to smell nice. While the beef and vegetables are cooking, dice the potatoes quickly into bite-sized chunks. Add the potatoes, box of broth, and seasonings to the pot. Cover, bring to a boil, reduce heat and simmer for 20-30 minutes, until potatoes are soft to the bite.

 Add the condensed milk to the pot, and heat over medium-low heat, stirring periodically, until hot through. Remove pot from heat and stir in the shredded cheese, stirring it as it melts. Taste and add salt, pepper, and more cheese to taste preferences if required.

 Serve garnished with shredded cheese and crispy onion bits.

This hearty cheeseburger potato soup can be made with aged cheddar cheese or spicy Monterrey Jack for a fast, hot, and filling winter meal! And it's got lots of hidden veggies in it, too. | FoodRetro.com | YMCFood | YummyMummyClub.ca