Sabtu, 06 Februari 2010

Burn Through in Stainless Steel Burners

I grill.

I mean, I grill – often. I grill about 3 or 4 days a week, every week of the year, every year. Living 100 yards from Lake Erie, this is no small feat: it gets cold in Cleveland in the winter, and we get our fair share of snow – most of which is lake effect, sometimes measured in feet rather than inches.

I have often found myself outside after dark on a late December evening, in 20-degree weather with an icy wind blowing in off the lake, snow half-way up my shins, basting a roast on the rotisserie.

Naturally, my wife thinks I am nuts. She also thinks I am a great cook, which is neither here nor there. But, I digress…

A couple of months ago, I noticed that the grill was heating unevenly. The left side was noticeably hotter than the right. The flame was higher on the left, and I had more problems with flare-up on that side. Meanwhile, the right side was not cooking very well at all. The grill is a 3-year-old Fiesta that my wife bought at K-Mart shortly before we met. It sports a stainless steel sheet metal burner which is adequate for occasional use. I suspected that the burner was burned through since I use the grill much more than the manufacturer intended; I wanted to replace it much earlier than this, but since we were buying a house, I placed the project on the back burner, so to speak.

The house threw us a couple of major curve balls, the worst of which was a total replacement of our kitchen. At the time, we were waiting on our new counter tops: we did not have a working kitchen; the microwave and the grill were our only working kitchen appliances. Nice time for the grill to fail, huh?

One night during the remodel, I wanted to grill some chicken. I fired up the grill, and noticed that the flame on the left side of the grill reached the cooking grate, and the flame on the right was barely noticeable. Our chicken browned noticeably toward the left side, and barely cooked on the right. The photos on our site show the old burner.

I muddled my way through the meal, deciding to take action. The next day I ordered a new burner/venturi set over the Internet. Since spiders love our new house, I splurged on spider guards. The only tools I needed for the job were a pair of pliers and a screwdriver. I assembled the burner/venturi assembly, connected the ignitor to the burner, and went out to the grill. I disconnected the securing pins for the burner underneath the grill and the old burner lifted out easily. The new burner settled gently into place, and I connected the ignitor and installed the spider screens. I tested the ignitor, and, satisfied that it worked properly, fired up the grill. Even blue flame, about one and a half inches high, with yellow tips. Perfect. Nice, even heat again. Project completed, and in about a half-hour.

So why did this happen? Why did my burner rot from the inside out? The answer is simple physics. When your burner burns gas, the flame outside the burner creates a vacuum inside the burner. An open valve allows gas under high pressure to flow from its source into the burner, where the pressure is lower, and then continue out to the outside to be burned.

So how does this cause burn-through? Remember the flame that is sucking the gas out of the burner? Now shut that gas off. What happens? The gas is still burning. When there is no more fuel, the vacuum inside the burner actually sucks whatever is right outside the burner, resulting in an audible “pop” when the flame goes out.

Here it is in a nutshell: you’ve been cooking food, right? You’ve been using spices, sauces and rubs -- and the food itself has its own juices. These are in the air surrounding the food and the burners, mostly as partially-burned carbon particles. These carbon particles get sucked into the burner when the flame is extinguished. These particles remain in the burner until the next time you fire up the grill. When you fire up the grill, these particles create chaos in the flow of the gas. The pressure of the gas will hold these particles against the sides of the burner. Reaching ignition temperature, they eventually burn through the metal from the inside out. Now you know why I had to replace my burner – and why you’ll have to do the same if you purchase a grill with a sheet metal burner.

My story points out another issue: what type of burner will your new grill have? This is a major decision that many overlook when they purchase a high-end grill. Most grills, even well-known $3,000 to $5,000 units, have the same stainless steel sheet metal burners that I just replaced, and many have a thickness in the 20- to 24-gauge range! Let’s face it: buying a $3,000 grill is like buying a Mercedes or a Lexus; you shouldn’t have to replace the engine in a 3-year-old Lexus!

If you purchase a grill with a stainless steel sheet metal (or cast iron/cast iron composite) burner, you will replace the burners at some point. The more often you grill, the more often you will replace the burner. The more expensive the grill, the more difficult the replacement.

"What?" you say! Stainless steel will rust? Well, yes, it *will* rust. It just takes a lot longer. The idea that stainless steel will neither stain or rust is a myth. The "stainless" in the term "stainless steel" refers to the fact that there are no impurities in the metal itself, and that nickel has been introduced into the alloy to produce a more acceptable finish. A lower grade of stainless steel with a lower nickel content will attract a magnet, also contrary to popular myth.

What, then, is the alternative to a stainless steel sheet metal burner? Cast iron? Well, yes, but many grill manufacturers also use cast brass or cast stainless steel, which will not rust or burn through. Lynx and Fire Magic are two such grills, and they’re even warranted against rust and burn-through. A less-expensive alternative with cast brass burners would be the Coleman 6000, retailing for under $1,000 (photo right).

This is not to disparage stainless steel sheet metal burners: Napoleon uses 16-gauge stainless steel in their burners, much thicker than just about any other brand, and they tend to last longer than other manufacturer’s burners. They are still prone to rot and burn-through, however: it just takes a little longer, that’s all.

So, if you’re shopping for a new grill, check the burner construction first.

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