Today, I want to take a look at three popular choices of torch fuels: butane, propane, and MAPP. All three are used by chefs in the searing process. This question arose after I began learning more about fuel gases being recommended for cooking use.
I first introduce each fuel before providing a summary of its pros and cons. Then, I include a comparison table of flame temperatures. Finally, I close with some thoughts on what I am doing with this gained knowledge.
Fuel commonly used in disposable cigarette lighters and camping stoves. An alkane, each butane C4H10 molecule is composed of four carbon atoms, saturated with hydrogen.
a butane molecule
Pros: It is widely available and affordable.
Cons: When bottled for sale, it is often mixed with small amounts of hydrogen sulfide and mercaptans, which give the unburned gas an offensive smell. Owing to its longer carbon chain relative to propane, butane is more prone to incomplete combustion.
Fuel commonly used in gas grills. Also an alkane, each propane C3H8 molecule is composed of three carbon atoms, saturated with hydrogen.
a propane molecule
Pros: It is widely available and affordable. Bernzomatic 16.4 oz cylinder available for $3.50 at your local hardware store. If you already have a gas grill, you don’t need to buy another fuel specially for torching.
Cons: Its flame temperature can’t reach that of a MAPP flame.
Aside: Propane is widely regarded as a terrific fuel gas for cooking use, though it would be wise to devise a method to fill a small bottle from a larger canister.
MAPP (methylacetylene-propadiene propane)
Wikipedia main article on MAPP gas: http://en.wikipedia.org/wiki/MAPP_gas
Fuel gas composed of methylacetylene (propyne) and propadiene. MAPP gas is a trademarked name belonging to Linde Group, previously to Dow. True MAPP gas production ended in North America in the spring of 2008, when production was discontinued at the sole plant that continued to make it. Current products labeled MAPP are made using stabilized liquefied petroleum gas with high levels of propylene. MAPP is notable for having higher flame temperatures and energy densities than any flame other than acetylene.
Propylene C3H6 is an alkene composed of three carbon atoms and six hydrogen atoms. The double-bonded carbon results in propylene having a lower molecular weight than propane, in spite of their both having three carbon atoms. This allows for more complete combustion relative to propane.
a propylene (propene) molecule
Pros: Propylene-based fuels burn cleanly and avoid tainting food with combustion products
Cons: MAPP is more expensive to produce (I’ve seen it cited as 1.5x the cost of propane), and the increased cost of production is passed along to the consumer. Going off of the list price of a Bernzomatic 14 oz cylinder for $9.95, MAPP is almost seven times the price of propane.
Aside: MAPP fuel came to my attention as I was reading The Cooking Lab’s Modernist Cuisine at Home (List $140, Amazon.com), prompting me to explore the author’s claims
Flame Temperatures of Butane, Propane, and MAPP
|Fuel Gas||Combustion with Air (deg C)|
Reference: Flame Temperatures for some Common Gases – Engineering Toolbox (http://www.engineeringtoolbox.com/flame-temperatures-gases-d_422.html). Note that the flame temperature of propane as reported in this table is different from that found on the source website. This change was made in consideration of the reported maximum adiabatic flame temperature for that fuel gas.
I will personally be investigating solutions for using propane gas in the searing process. It does away with the incomplete combustion issues associated with its heavier alkane cousin, butane, while keeping the cost multiple times lower than MAPP gas.
I wonder what type of propane torches are on the market, specifically targeted for cooking use. Torches like the Iwatani professional cooking torch (~$27, Amazon.com), mentioned in my search for a butane torch for sous vide cooking, have flow control. I’d rather not ape this guy:
… though I do have a Weed Dragon Red Dragon (~$50, Amazon.com) lying unused in the garage…