I would bake the cake without the lid and ring, and put the lid and ring on after the cake has cooled.

I would trust it for safety as long as I would trust baked goods that sit out on my counter.

Here's what the NCHFP says:

Can I can bread or cake in a jar?

These products are not recommended for canning; choose recipes that you can freeze. In fact, most of these products are not really "canned." The directions call for baking in the jar and then closing with a canning lid. Many recipes for quick breads and cakes are low-acid and have the potential for supporting the growth of a bacteria like Clostridium botulinum if it is present inside the closed jar. One university's research showed a high potential for problems. You will see these products made commercially; however, additives, preservatives and processing controls not available for home recipes are used. Canning jar manufacturers also don't endorse baking in their canning jars.

The likely hood of the jars blowing their sides out when the cake or bread is rising during baking, since they are so confined with lid and rings, sounds pretty scary to me.

I see no reason to "bake" this way. I wouldn't eat it even after just 24 hours.

Nancy

Please, do not do this ! Not only can you possibly get botulism, the jars can shatter as you open the oven and get glass shards all over or they can cut you. They are not meant for dry heat like that.
If you want to bake little round cakes, then use a metal can.
Oh, and it only takes about 2 days to grow enough botulism to kill a person.

Occasionally using unapproved methods for our own consumption is one thing but giving potentially unsafe things like this, a practice that hasn't been approved for years, as gifts to others is something else entirely.

Please don't do this.

Dave

Now if you were in Australia or New Zealand you could use a nut loaf tin. I love these. Both ends come off for easy removal and they make great date breads.

Occasionally one in the U.S. will come up on ebay. Just a fun extra.

Carol

Here is a link that might be useful: Vintage Nut Loaf Tin

Pampered Chef sells those - I bought one at Goodwill to use for DD's Rapunzel cake, but since both ends come off and it leaked when I washed it, I didn't trust it for cake batter. Bread dough would be fine.

BTW, I ended up baking DD 2 cakes (one on her Bday, one for party later that w/e), used pint WM jar for 1st, it was fine, 3C WM for the 2nd, that came out OK but sagged a little in transport. Of course I greased the jars well, filled app. 2/3 full, started in cold oven, and cut off the tops after cooling slightly, then unmolded. Baking with tops on, or putting lids on to seal while cooling is just dangerous. My jars could have shattered even with starting in a cold oven but it was an experiment, and I did wear eye protection when I took them out just in case (thought cracking while cooling might have been more likely than shattering, if they didn't explode in the oven, but wanted to be safe).

Thanks for the replies everyone. I suspected it wasn't safe due to possible botulism, and now I also know that the jars can shatter in an oven. Good to know. It will not be easy to tell my friend but I will pass this on to her.

By any chance would storing the cakes-in-jars in the refrigerator as soon as they've cooled, eliminate the threat of botulism?

I saw a few fruit cake recipes done, but like someone wrote above the lids/rings were placed on the jar after they cooled.

Another topic from this is that I have been reading a book called "The Blue Chair Jam Cookbook". This company places the clean jars in the over to heat, then fills the jars with jam, places the lids/rings on them and then places back into the oven for processing.

Thoughts?

Andrea

By any chance would storing the cakes-in-jars in the refrigerator as soon as they've cooled, eliminate the threat of botulism?

No, that isn't the way botulism works. ;) Refrigeration would make no difference.

This company places the clean jars in the over to heat, then fills the jars with jam, places the lids/rings on them and then places back into the oven for processing.

Very old school methods and not approved for many years. Check out the guidelines at NCHFP and you'll find the safety issues associated with these particular practices discussed in detail in the FAQs there.

Dave

There is a technique for using the nut loaf tins. They are designed for more dense quick breads or yeast breads, not cake batter. For that I think you'd have to wrap around the bottom, as with a cheesecake in a water bath.

Also, some people aren't aware they're used standing up, not resting on their sides, and they're placed on a baking tin to catch any drips (though with the right recipe that won't happen.)

Regarding the cakes in a jar, you could bake without any lids or rings, cool thoroughly, then apply a lid and refrigerate or freeze. The issue is applying lids over hot cakes. You're forming a weak seal and creating conditions where botulism is possible. (I don't know of any cases yet, but the point is it can happen.)

I'm not speaking of the glass issues, just the cake issues.

Another option would be to bake in borosilicate glass, which can be heat stable up to 935 degrees. I was contemplating using some canisters I have, but haven't made the attempt yet. At the link I've shown a borosilicate canister. I don't see any reason why you couldn't bake in the glass (sans lid) and when cooled remove and wrap for storage like any other quick bread or cake.

I have the Blue Chair book but haven't looked at it yet to check out their "canning" method. (Using an oven isn't canning.) There would be risks with the stability of the jars, but you don't have food safety issues with a high-sugar high-acid product.

I do think they're wasting energy, though. They might as well just open-kettle and skip the oven "processing." Same results.

Carol

Here is a link that might be useful: Bodum Borosilicate Canister

Ladies! Canning cakes is NOT safe! I did months of research and there is no way to make sure that your cakes don't have bacteria when they go overseas. I wanted to start a business that would allow me to send pre-cooked cake to the military men and women overseas.

However, after much research, I decided that the health hazards of sending pre-cooked cake are too high. In fact, the shipping methods used today have the cake approaching 116 degrees which could allow for a break of the jar seal or botulism. Please do not send cake in a jar unless you know exactly what you are doing.

Here is what I did instead! Along with 5 other teammates, I began the process of building a product that would allow people to safely send that slice of home. My product is named CourageCakes! It's a completely customizable cake in a jar. All you have to do is ADD WATER and MICROWAVE for 30 seconds. You can send a personalized message, drawing, or photograph along with a delicious piece of cake to your loved one. Imagine their face when they open the package to see that you sent them a photograph of your child on their first birthday!

We encourage everyone to continue making their own renditions of cake in a jar, but we also encourage you to take the necessary precautions to make it safely using FDA approved guidelines.

Please check us out at www.CourageCakes.com

You can also follow us at: https://twitter.com/#!/couragecakes

Cakes will be available starting April 1st 2012.

Here is a link that might be useful: CourageCakes

Thanks for all the replies everybody. Well I passed on a link of this to my friend as well as some other web site links about safe canning, but she has decided to go ahead and do this anyway. She believes it is okay as long as she tells people to refrigerate the jars right away and eat them in a few weeks. I didn't know what else I could do to convince her not to, so I just won't be eating any of them myself or letting my family have them. I hope we here are all just being overcautious about this, because it would be said if somebody got ill due to cakes in a jar.

Everyone has to choose their own comfort level when it comes to risk taking. Some accept none at all, some achieve a moderate balance, and some are apparently comfortable with a great deal of risk. Nothing will change their minds and they will get quite hostile if you keep trying. All you can do is offer the info and move on.

Dave

If you bake your cake or cupcakes by themselves, then put them in the jars by hand, there's no risk. This is what I do. Frosting, slice of cake, frosting, slice of cake, frosting. Then add lid. I freeze them and ship them.