Choosing and hitting BTU/hr targets with propane burner heads for canning

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Poindexter

Minister of Fire
Jun 28, 2014
3,125
Fairbanks, Alaska
More than one way to skin this cat.

Wife and I are canning salmon and tomato this year, the latter as recipe ready, ketchup and salsa. Our canner is rated for 24k btu/hr, max. Once it is up to temp and pressure it doesn't take a very big flame to maintain. The Presto line, from internet research, is generally limited in the manuals for each to 12k btu/ hour. Ours is an All American 921, I don't know the max btu/hour for the rest of the AA line.

My mom canned a little bit indoors, she blew up a pressure canner one afternoon inside the house and started freezing pretty much everything that could go in a zip loc bag. My grandma, her mom, canned everything she could get her hands on, indoors, in Kansas, even when outdoor ambients were +108dF. Just open a window and have some iced tea dear.

There is a group of inexpensive propane grills out there rated at roughly 30k btu/ hour, but they typically have a linear burner, a line of flame that won't fit under a canner very well, not a round burner.

The short version is you need to choose between natural gas from a buried hard line and find out your local price and delivery pressure; or choose propane and figure out what can meet your needs.

I bought two propane burners at a yard sale yesterday AM, the previous owner used to boil birch sap down to birch syrup (maple is better), the burners I bought came with sturdy stands that can support my canner, and burner heads rated at 58k btu/ hour. I paid $20 for the pair.

First pic is one of the burners I bought, after cleanup, adjacent to the rust I brushed out of the pair. This is clearly a very common burner on amazon, they are under $20 for the bare burner head. Be advised a "propane burner" usually has legs on it, a "propane burner head" is the thing you need to choose.

A visibly rusted propane burner head is not going to work right. You got to take it apart and get busy with a wire brush cleaning out the burner grooves in the top plate and the cup the top plate fits in. You do not have to polish the tube where the fuel and air mix, but get the big chunks out. Screws on mine were #10x24 at 2.5 inches. I did use some high temp anti-seize on the screw when re-assembling the burner heads. Coming soon to a hardware store near you, metric threads.

I am not a certified gas technician, and I do not have a calorimeter. I am estimating btu/hr from my propane burner heads based on my empirical experience with my oil fired boiler - 100-120k btu/hr, my propane fired weed burner (50k btu/ hr) my BK wood stove (50k btu/hr max output for the 30.2) and my electric cook stove with four burners and an oven on a single 220v/50a breaker.

58k btu/ hour would require a 220volt breaker at 80 amps. My indoor cookstove is on a 50 amp breaker. I have done a 2 gallon boil on the electric cookstove for home brewing beer. It was brutal and lengthy.

I am fairly confident the pictured burner head is capable of 58k btu/ hour on a 0-20 psig regulator with a #45 drill size (0.085") orifice at full roar. I have done it and this thing is a monster. What this burner cannot do is run efficiently (blue flame with yellow propane tips) much below about (ish) 25-30 k btu/ hour. Second pic is my canner while maintaining 10-12 psi in the canner for 110 minutes. I probably was needing about 5-10k btu/hour to maintain temp in the canner during the processing time.

So for canning, on the one hand you want max BTU to bring everything up to temperature quickly, but once the canner is up to temp I don't want to be paying $5.00 per pound for propane that ends up as soot on the outside of my canner that needs cleaned off. Running the above setup requires the air shutter on the burner head to be more or less fully open.

For my other identical burner head, I am using a regulator rated 0-10 psig (squirrel!) and a gas orifice at #60drill bit, (0.0400 inches). Clean burner head. For pic three, I have the air shutter a bit more than halfway closed, and a contender for pressure canner maintain small efficient flame. For the last one, with the fuel at full roar and the air shutter unchanged, I have about (ish) 30k btu / hr I think.

I am close enough to run a second batch through the canner. I suspect I can get two canned batches out of one full BBQ tank, but I am not sure yet.

For my All American canner the caution in the manual is flame should not be coming up the side of the canner kettle. That will cause the kettle to heat unevenly and lead to sealing problems at the lid.

So for psi v- psig imagine you have an empty pressure vessel, no valve on the top. Maybe a scuba tank. It is open to the atmosphere, 14.7 psi inside and out. Get some pipe dope, screw a valve into the top of the scuba tank. If you measure the absolute pressure in there, it is 14.7 psi. If you put a scuba gauge on there, it is going to read zero psiG, because psig is measured pressure minus ambient pressure. If you got a precise enough gauge on your scuba tank and don't breathe, you could calculate your depth underwater by watching the psig drop as you go deeper and deeper underwater. If you took the "empty" tank with you filled to 14.7 psi at zero feet above sea level, it would actually display a negative pressure psig as you take it deeper and deeper.

If you are running an All American canner other than the 921, I haven't read your manual, and don't know your max btu/ hr. If you got a Presto and need 12k btu/hr max, try looking at wok burners on amazon. The small ones might work for you. I did find a 25k btu/ hr wok burner on Amazon, made in Tennessee, but it is not available with no due date. I was going to call them Monday, but I think my 0.0400" orifice with 0-10 psig regulator is going to work for me. I have enough confidence to try another cook with 0-10 psig regulator, 0.0400" orifice and $70 worth of salmon in 19 half pint jars.

There is a metric spec for gas orifice sizes. Caveat emptor, you have been warned. The math is straightforward when you realize it needs to be done.

The upside to canning outdoors is you aren't heating up the house in high summer. The downside is Mr. Wind can blow your burner out for you, and you got to do celebrity chef stuff to get the burner relit before your system drops below minimum target pressure during the processing time. I am really looking forward to canning some berries. Eight minutes at 10psi is going to be a cake walk.

There are a frustrating number of food bloggers out there running 58k btu/hr burners under their pressure canners and raving about how fast they can get the system up to processing temp/press. Whether or not they have gotten away with that cycle after cycle, year after year, to quote the movie _Chef_, "that was left ambiguous."

I would not choose the burner head I have if I needed 12k btu/ hr as my max. The closer you are to full roar, max throttle, the harder Mr. Wind has to work to blow you burner head out. If your burner head needs full throttle to make 12k btu/ hr, your are still going to be near half throttle to produce 5k btu/hr once you are up to temp- and you will have come wind resistance in your pocket.

For now I am keeping my fat orifice and 20 psig regulator, but if my small orifice and 10 psig regulator meet my needs for water bath canning I will send the fat one down the road to a syrup maker. High BTU for getting the canner up to temp is good, but for raw meat especially, efficiently maintaining temp is more important.


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Poindexter

Minister of Fire
Jun 28, 2014
3,125
Fairbanks, Alaska
So I learned 'some' stuff today.

I started at a fuel terminal, largest local propane dealer, it is where they fill the propane BBQ tanks on the exchange system all over town. The gal at the counter was able to explain to me that propane tanks are sold by capacity in pounds, but propane product is sold by the gallon. There are 3.14 pounds of propane in one gallon. I suggested that "should be easy as pi to remember," she had heard that one before.

So the common small BBQ tank, the 20# tank, well, it doesn't actually hold (20/ 3.14) 6.3 gallons, it holds 4.x something when empty, 4.6, 4.7, something like that. Tank price goes up faster than capacity, I guess maybe the larger tanks need thicker steel. They wanted $77 for a new, full 20 pound tank this morning. A new full 40# tank was a fair bit north of $300 cash and carry.

I did not find anything useful at team blue homestore today. At team orange I found a fixed output regulator ( 11 inches water column) with a 2-3 foot hose on it for $25. I looked at a bunch of gas BBQ grills at WalMart. The fixed output 11"WC regulator is ubiquitous on gas BBQ grills, even my 11 year old one at home, and the side burners on these are often rated at 10-12 k BTU/ hour.

Gas grills are not typically well enough built to support a full canner on the sideburner, but if you find a gas grill with a side burner on a curb somewhere, there is hope. You need all the hardware from the male threaded fitting that accepts the gas line to the burner. The fuel orifice or jet is going to be in that assembly, you need the flame adjust knob to work, and the air shutter. If it has a fuel line and regulator on it, try them. The single stage regulators are clearly throw away diaphragm types, they either work or not. Hook it up, open the tank valve, check for leaks. If it is leaking, $25 at a hardware store, I am sure those are on Amazon too. Now all you need is to build a fireproof support that can support the canner and you can bolt your burner to. You might could take out the burners in the grill area and move the sideburner into that central area.

11 inches of water column pressure works out to 0.4psi. You can get a LOT of BTUs out of that. With ten feet of 1/4 " ID pipe and no fittings to add resistance to flow, it can support 35,000 BTU/ hour. With wider lines and shorter lengths 11"WC can support a LOT more BTU/hour.

I am awaiting a return phone call from the manager at the fuel terminal. The counter gal was not sure what burner head I would need for 25k BTU/ hr, and they didn't have any burner heads on display in the showroom/ office area.

I am still not crystal clear on the difference between low pressure propane and high pressure propane. I am pretty sure that some folks are confusing the LP in LP Gas to mean low pressure. I am pretty sure "LP gas" is referring to "liquified propane gas," a product that is sold as a liquid by the gallon, but produces vapor in the pressurized headspace of the tank. My hypothesis is the fixed regulators at 11 inches water column are delivering low pressure propane (0.4 psi), while the larger adjustable regulators rated 0-10, 0-20psig and etcetera are the high pressure ones.

And the darn birds found my honeyberry bushes today. I was kinda thinking I could make some honeyberry jam this afternoon, but those rascals picked me clean while I was at the office this morning.
 

Poindexter

Minister of Fire
Jun 28, 2014
3,125
Fairbanks, Alaska
A used BBQ grill was found at the solid waste transfer station this afternoon, and brought home for dissection in the interests of science.

The main body of the grill was found to have active metastatic rust disease, body cancer, and adjudicated not a surgical candidate to support a loaded pressure canner even over the main cooking grates. The donor was then sedated humanely and efficaciously with a 4# sledge hammer, the gas side burner removed, and the remains returned to the solid waste transfer station in a dignified fashion, with no pain visibly evidenced by the donor per anesthesia, all participating OR staff and the operating provider.

Gas hose with fixed output regulator at 11 inches water column was found to have a wye on the output hose, a common finding among gas bbq grills with sideburners, and crimped fittings. One output leg of the wye feeds the side burner, the other the main cooking burners within the grilling area. Crimped fittings cannot be adjusted without significant investment in floor standing hydraulic equipment, thus the hose was returned to the transfer station with the rest of the remains of the dearly departed, as this side project is already janky enough.

In a healthier donor, removing the entire side shelf with included burner and relocating to the central grilling area remains a possibility with perhaps tin snips and a few sheet metal screws.

The recovered burner is rated for LPG at 0.5psi and is complete with control knob, gas jet, air shutter and burner assembly. In general appearance it should be capable of 10-15k BTU/hr when in good working order.

Perversely, there is an included angle between the axis of the harvested burner head and the harvested gas jet/ control knob. This abomination in the eyes of God Almighty will be a problem for the surgeon transplanting this organ into a recipient, organ harvest is completed.

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begreen

Mooderator
Staff member
Nov 18, 2005
100,872
South Puget Sound, WA
Nice scavenge, we can no longer do that at our transfer station. When I bought our propane tank a 20# was more like $50 full. I got two additional tanks from yard sales for $5 each with gas in them. Our 100# tank was around $120 about 5 yrs ago when I bought it. I see they are twice that price at Tractor Supply now.
Yes, a 20# tank takes about 4.6 gal of propane. I believe they can't be filled all the way or they would vent out gas as they warmed up.
I bought a 60k BTU burner from Big Five on sale for $69 for beer brewing. It has enough power to raise the 2.5 gallons of water to a boil in about 30 minutes, yet can be turned down low enough to maintain the low boil without burning the wort. I brew outside, preferably on a day with no wind. The other advantage of outdoor brewing is that I can run the output from the wort chiller to the drip irrigation system.
 

Highbeam

Minister of Fire
Dec 28, 2006
20,531
Mt. Rainier Foothills, WA
I too use a turkey fryer for beer brewing. Rapid heat up and very low roll for brewing. But to maintain 10 psi in a pressure vessel with a tiny controlled vent takes way less heat.

I own a presto canner. The all American brand cost several times more for the same function so I chose to learn on a presto. These things are fired up with a few inches of water in the bottom of the vessel so high heat whipping up the sides could overheat the aluminum walls above the water line. Too much heat during the long cook could boil the vessel dry so you need a very low output.

People have been pressure canning for a long time. I believe we are over worrying and the vessels are far more robust but the owners manuals do give warning.
 

begreen

Mooderator
Staff member
Nov 18, 2005
100,872
South Puget Sound, WA
Yeah, we have a stainless pressure cooker that my wife stopped using years ago. It's built well, but my mom scared her when visiting once with tales of when one blasted the contents all over the ceiling on her. With 5 kids my guess is that she was more than a little distracted.
 

Poindexter

Minister of Fire
Jun 28, 2014
3,125
Fairbanks, Alaska
Appreciate the discussion. Once I have a 12-15k btu/ hr burner up and running I will do some time trials.

So far canning salmon x3 runs (10psi for 110 minutes) I am finding it takes me about an hour to get from lighting my 24kBTU/hr burner to the jiggler starting to jiggle (or the rattler starting to rattle if you prefer).

I am running the canner in the drive way an using the garden hose to put water in the kettle, and I am trying to be gentle with my food. When I light it up I got salmon fresh from the fridge, room temperature canner, jars kinda warm that just came out of the dishwasher, and water around +45dF that just came out of the garden hose. I am running my 24k burner pretty close to 12ish k btu/ hour while everyting gets to the same temp, and only running the burner at near 24k BTU/ hr for a very few minutes once everything is hot to get to active steam.

I am not sure I am really saving any time with a 24k btu/hr burner compared to a 12k btu/hr burner, hope to find out soon.

I have had my infrared pyrometer out and working pretty hard. One thing I notice on my canner is the temperature of the lid runs about 10 minutes behind the temp of the kettle - so I have plenty of evidence in support of letting steam vent for ten minutes before putting the weight on the vent. Pressurizing a vessel at uneven temperature seems like a really bad idea.
 

Wood1Dennis

Burning Hunk
Jan 17, 2016
203
Eastern Wisconsin
Sorry about bring up an old thread, but for some reason it caught my eye.
Have any of you ever looked for a propane burner at a home brew store? I use my Edelmetall burner for canning all of the time. At 72,000 BTU it brings my canner up to boil in no time but can be throttled back with good control. That is a real advantage when boiling 7 gallons of beer wort. I have only used it for regular canning, I do less pressure canning and I have always done it on an electric range. Now I want to try the propane burner for that too. I love that I can keep the heat outside and how fast it works. Link to the one I have is attached below.
 

Highbeam

Minister of Fire
Dec 28, 2006
20,531
Mt. Rainier Foothills, WA
I’d like to think that pressure canning is regular canning but whatever. My presto pressure canner specifically forbids the use of turkey fryer or other outdoor type propane burners. 12 or 15k btu limit. I brew beer on a turkey fryer and that high btu burner is very tempting. Instead I go a bit slower on the glass top electric range, but it’s not too slow. Most of the time is the pressurized time.
 

Poindexter

Minister of Fire
Jun 28, 2014
3,125
Fairbanks, Alaska
@Wood1Dennis I have pretty well settled on a 3 burner propane setup.

I have a 50k BTU/hr burner, pretty much a turkey fire burner. I use that (not very often) mostly for blanching potato cubes when hot packing potato. 15 gallon cauldron for that beast.

I have the 15k BTU/hr burner (salvaged from a BBQ grill) that I typically use for either boiling water and heating jars in my 5 gallon stock pot, or cooking fruits or tomato prior to hot packing. For tomato I will have the hot jars immersed in hot water in the cauldron on the 50k burner, while the tomato is simmering.

Finally, I have a 25k BTU/hr burner that is usually under my AA921 canner. The manual for mine says 24k BTU/hr max, I haven't read your manual. However, I hardly ever run it full throttle.

When pressure canning a LOT of salmon- my personal best is 114 half pints in one very long day- I run one AA921 on the 25k burner and my other AA921 on the 15k burner. Typically I can do three loads on 25kBTU in about the same time it takes to run 2 loads in my other AA921 on the 15k BTU burner.

I feel like I have a pretty sweet setup for a one person operation. If I was going to be team canning looking for high output I would get a second 15 gallon cauldron and a fourth burner around 20-25K BTU/hr.

For water bath processing I have a Fruit Saver Steam Canner that runs fine on my indoor cooking stove, or the 15K propane burner.
 
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