16 replies to this topic

[jrshaul]

I recently found a recipe calling for something rather novel, to me at least: Boiling an entire can of sweetened condensed milk to produce zero-effort dulce de leche. In theory, a can can support the pressure for an hour; in truth, no one's entirely sure.

It's a nice solution to a tricky problem - there's quite a few recipes, including several for pumpkin pie, that spec the pressure cooking to caramelize various ingredients. I don't even own one.

BPA aside, how likely am I to fill my kitchen with shrapnel?

[heidih]

We have discussed the dulce de leche cooked in the can (in general discussions about d de l) :
http://forums.egulle...age__hl__+dulce
http://forums.egulle...ch&fromsearch=1

I did it once and was not exactly blown away with the results but I have never had it prepared in a traditional manner- so no basis for comparison

I had not heard of other items like pumpkin cooked that way. I am interested to see what folks have experienced.

[pazzaglia]

Maybe you are referring to this?
http://www.hippressu...ensed-milk.html
My recipe only calls for the can to be at pressure for 20 minutes.

It is actually safer than boiling a can in an open pan, as a pressure cooker is designed to hold high pressures. So, if the can were ever to go, it would be in a very safe place for it to do that. I have never heard of an actual exploding can. I have heard of people trying to open a hot can and the contents spray out (in an explosive manner because of the pressure difference).

There are a couple of other safety points worked into my recipe that many others lack:

- Do not pressure cook a dented or warped can (the damage will affect the can's resistance to pressure)
- Do not jostle a can under pressure
- Immerse the can in water fully (to avoid quick temperature/pressure changes)
- Let it cool overnight (to ensure the contents are fully cooled)

It is also important to note. That canned foods are "canned" because they have already been pressure cooked in an industrial pressure cooker to sterilize the contents and delay spoilage - so they have already resisted what is likely higher pressure before.

The results are shelf-stable, so if you know someone with a pressure cooker, you can ask them to pressure cook a couple of cans for you so that you have the dulce handy for when you need it.

Tell me more about your theory that a can can hold pressure for up to an hour?

Ciao,

L

Edited by pazzaglia, 19 November 2012 - 10:50 PM.

[pazzaglia]

Heidih, I checked the topics you linked to, none of the covered making dulce e leche with a pressure cooker.

Ciao,

L

[budrichard]

"There are a couple of other safety points worked into my recipe that many others lack:"

Your method is not safe.
You note about can already being pressure cooked, results from not understanding Thermodynamics and Heat Transfer.
The liquid in a pressure cooker is kept at a constant temperature and therfore pressure by the pressure control valve, releasing pressure, transfers heat away from the cooker, keeping the temperature constant. should that control fail, there is a pressure relief valve that will do the same thing.
A can inside a pressure cooker with the liquid at the same temperature as the liquid in a pressure cooker will be at a zero pressure differential state and consequently, zero stress, in short, they have NOT resisted higher pressure..
Any vessel that is made in the USA that contains pressure is constructed to ASME (American Society of Mechanical Engineers) standards and that is the reason boilers don't fail or fire extinguishers don't fail, they are ASME vessels.
A common 'tin can' is not designed to be heated unless the can is opened. It would be possible for the can in a pressure cooker to achieve a temperature higher than the bulk liquid in the pressure cooker because the can is resting on the bottom of the cooker and you will have conductive heat transfer from the heat source through the bottom of the cooker to the can.
The only reason you have not had any problems is dumb luck.-Dick

Edited by budrichard, 20 November 2012 - 12:28 PM.

[pazzaglia]

If you bothered to click the link, you would have seen the can is pressure cooked in a steamer basket to avoid direct contact with the base of the cooker.

Ciao,

L

Edited by pazzaglia, 20 November 2012 - 12:37 PM.

[gfweb]

My safety concern is mostly with moving the superheated cans anywhere before they cool. I'd leave them in the pressure cooker overnight to cool without moving them.

[Baselerd]

I made this before somewhat - but transferred to a mason jar instead of cooking directly in the can. There has been a lot of controversy over the plastics used in canning recently - I figure best to just not worry about it and use another container.

With that said, my dulce de leche turned out great.

[jrshaul]

To be more specific, I was referring to the use of the can as a pressure cooker in of itself. I don't own one, and the infrequency of use doesn't justify purchasing one of quality. (Apologies for missing the other results - I'd been searching for "boiling" and "can.") I'm using the end result to make an old-school Banofee pie, though I have been advised that pressure-cooking commercial pumpkin puree can do wonders for the flavor.

Edited by jrshaul, 20 November 2012 - 02:17 PM.

[Catherine Iino]

I will confess that I have made dulce de leche a score of times by simmering cans of sweetened condensed milk in a deep pot of water. I actually discovered this method long before I discovered dulce de leche. Half a century ago, I saw one of those i-hate-to-cook kind of cookbooks that had this "recipe"--probably called something like "Spanish Dessert"--and I was fascinated. I might be up to my ears in bpa, but I haven't--yet--had a can explode.

[Broken English]

I've done it at almost every restaurant I've worked in, so long as the liquid is always covering the can, and the cans are not damaged, there is no problem.

I've cooked them for up to 3 hours without issues, just allow enough time for them to properly cool (I'd advise against an ice bath though, for no real reason other than I've never seen anyone do it).

[haresfur]

To be more specific, I was referring to the use of the can as a pressure cooker in of itself. I don't own one, and the infrequency of use doesn't justify purchasing one of quality. (Apologies for missing the other results - I'd been searching for "boiling" and "can.") I'm using the end result to make an old-school Banofee pie, though I have been advised that pressure-cooking commercial pumpkin puree can do wonders for the flavor.

If the can is heated in boiling water the temperature inside will equilibrate to 100 C - not the same as a pressure cooker.

[jrshaul]

To be more specific, I was referring to the use of the can as a pressure cooker in of itself. I don't own one, and the infrequency of use doesn't justify purchasing one of quality. (Apologies for missing the other results - I'd been searching for "boiling" and "can.") I'm using the end result to make an old-school Banofee pie, though I have been advised that pressure-cooking commercial pumpkin puree can do wonders for the flavor.

If the can is heated in boiling water the temperature inside will equilibrate to 100 C - not the same as a pressure cooker.

I was wondering about that.

I think I need to pick up a proper pressure cooker. Time for Craigslist!

[naguere]

When camping in France, the tin of meat/lentils always goes in the pot along with the spuds and all. the trick at the end is to splash a cup of water on the can, then using a cloth to cover then pierce the can. all will be well and your meal is ready.

[budrichard]

If you bothered to click the link, you would have seen the can is pressure cooked in a steamer basket to avoid direct contact with the base of the cooker.

Ciao,

L

Well I did indeed skim the link you provided.
What also caught my eye was the number of cautions you provided.
I stand by my original conclusion, "Your method is not safe".-Dick

[Gregg]

I will confess that I have made dulce de leche a score of times by simmering cans of sweetened condensed milk in a deep pot of water. I actually discovered this method long before I discovered dulce de leche. Half a century ago, I saw one of those i-hate-to-cook kind of cookbooks that had this "recipe"--probably called something like "Spanish Dessert"--and I was fascinated. I might be up to my ears in bpa, but I haven't--yet--had a can explode.

Exactly the same experience here. Countless batches, no explosions, bulged cans, no runs, no drips, no errors. I do not like the final product as much as traditional dulce de leche, it is a touch grainy and just doesn't have as deep a flavor, but it is EASY. At our elevation, about 1500 feet above sea level, it takes 2 hours 45 minutes. We usually do 3 or 4 cans at a time. They set in a steamer basket in the bottom of a stock pot and are completely covered in water (think of a water bath canner). We start out with cold water and heat it until the water us just at a VERY low boil. No reason to bounce the cans around, the water temp is the same regardless of boil rate. After the allotted time we just take the cans out, let them cool to room temp and then keep them in the fridge. It should be shelf stable, we just do that out of habit. Of course you will want to transfer it out of the can once opened.

Edited by Gregg, 26 November 2012 - 01:44 PM.

[OliverB]

I did this once a year or so ago, when it showed up here. I don't quite remember, but I think I had it in the steamer basket or on top of some sliverware. Then I put the lid on the pot and tied it down with a bungee cord just in case. Nothing exploded.
Once I was done I had the cans sit on my counter for a while before I put them back in the pantry. Where I think they still are, probably good to throw out by now, LOL.

But the cans did not bulge, looked the same after. So that part seems rather safe. I'd still tie the lid down again, just to avoid a crazy mess. But since I'm not really into sweet stuff, I probably won't do this again. Made it out of pure curiosity back then and never found a use for my "product".