A Historical Perspective
In 1948 when Char-Broil® entered the arena of outdoor cooking, all grilling was done over a charcoal fire, a type of fire that when fully developed to a bed of red hot coals, emits around 70% of its heat by radiation. By the 1970s, Char-Broil® and other companies had developed gas barbecue grills which brought convenience, control and cleanliness to the outdoor cooking experience. Attempts to mimic the performance of charcoal by the use of lava rocks, inert briquettes, burner shields and the like, however, have not been fully successful due to the difficulty of precisely managing the large volume of hot gas produced by gas burners. This characteristic has led to gas grills that cook with as much as 50% convective heat (i.e., hot air) and usually with considerable propensity to flare up and flame under the food.
Char-Broil’s new TRU-Infrared® brand grills actually return to the high-radiant model of charcoal with each of the grills producing over 65% of its heat by radiation and each possessing a unique construction that prevents flare-ups and fires while maintaining the speed and versatility of gas fuel.*
Over the course of more than six years of research and development, Char-Broil® has developed an intimate knowledge of the advantages associated with infrared grilling. Conscious of the need for outside and unbiased confirmation, however, Char-Broil® set out to scientifically quantify the benefits of cooking on Char-Broil® TRU-Infrared™ grills.
An independent test lab was engaged to quantitatively measure the moisture retention and efficiency of the Char-Broil® TRU-Infrared™ grills.
The challenges of instrumented food testing are two-fold. First, there is no standard method for testing, say, moisture retention. When Char-Broil® had a literature search done for academic work comparing different cooking methods, the 19 most relevant papers used 19 different methods. Secondly, statistical significance must be established since single tests can and do yield opposite results to averaged repeated trials. Therefore such instrumented testing is time consuming and labor intensive from the point of view of both data gathering and analysis, limiting the number of products that can be reasonably tested.
The choice of product to test can be done from a number of points of view, such as comparable size, comparable price point, and so on. Since no one had not done this before and we were interested in exploring the range of characteristics of different kinds of systems, we chose four grill that represented different systems. Two were TRUIR grills with two types of near field IR cooking systems with and without ventilation of the exhaust gases through the cooking grate. There were two convective grills, one with a very well developed system of a deep firebox and acutely angled heat distribution bars and another with a simpler system of a shallower firebox and wider, flatter burner shields. Both the convective grills were popular and well known competitive products. Results will vary if different specific models of representative systems are tested. We have no reason to believe Char-Broil® convective products similarly configured would have performed any differently.
After consultation with a veteran butcher, the decision was made to utilize 2”x2”x1” forward cut pork loin squares to be the testing protein as opposed to ground meat patties because pork loin is considered, by industry standards, to be a “stable meat.” “Stable meat” meaning the variables such as meat consistency (fat vs. lean) and meat texture and of pork loin is inherent and likely repeatable.. The cubes were cooked one at a time at four locations in the center of the four quadrants of the grill grates. They were cooked on a preheated grill for 4.5 minutes with the lid closed – and the remainder of the time with lid open – until 160°F internal meat temperature was reached. The test method chosen, cooking for 4 ½ minutes with the lid closed and then opening the lid to complete cooking, was considered to be reflective of real world use where cooking is done with both the lid closed and opened to flip, rearrange, and observe the food. There was variation of results from batch to batch of meat (five trials of each test were done), but trends relating to moisture retention – measured through weight loss as a percentage of maximum possible weight loss, gas use efficiency, time of cooking, and evenness of cooking – were clearly demonstrated.**
In the quantitative lab testing, results showed up to 44% improvement in individual tests of the TRU- Infrared™ grills over competitive grills in moisture retention as measured by weight loss. The tests also found that cooking times for the TRU-Infrared™ grills were 25% to 75% less than cooking times for the competitive grills, and consequently the amount of propane gas used was 44% to 84% less due to shorter cooking times and higher thermal efficiency of the TRU-Infrared™ cooking system. In addition, TRU-Infrared™ grills showed 77% to 83% less variation in cooking times across the different positions on the grill, exposing the efficiency of the infrared system across the entire burner surface. According to the testing lab, the Char-Broil® TRU-Infrared™ grills “were the better performing grills with more efficient results that produced shorter cooking times which resulted in less BTU/hr usage and less moisture loss; these characteristics will result in fuel cost savings and a more desirable cooked food product.”
Food cooked on a Char-Broil® TRU-Infrared™ grill is juicier.
Cooking times –Cooking time (in minutes) was shown to be 41% to 76% less on the best TRU-Infrared™ grills over the course of multiple trials averaged over development and replicated testing.
Moisture Retention –Results show a range of 22% to 39% improvement of the best TRU-Infrared™ grill over competitors in moisture retention as measured by weight loss in multiple trials averaged over development and replicated testing.
Gas Usage – Data shows that the best TRU-Infrared™ grills used 59% to 86% less BTUs than competing models, significantly reducing overall gas usage (as determined by multiplying cooking time by the BTU rate of each grill averaged over multiple runs of the replicated tests).
Evenness – Tests show 83% to 87% less variation in cooking times across each quadrant of the best TRU-Infrared™ cooking surface compared to competing grills, averaged over multiple runs of the replicated tests.
Infrared Grilling in the Media
Vivian Wagner, a writer for TechNewsWorld gives her thoughts on where infrared grilling stands in the marketplace and the future of grilling.
* The benefits of the increase in IR can be best looked at as the benefits of the reduction in convective heating. For example, a grill with 55% IR has 45% convective heating while a grill with 70% IR has only 30% convective heating.
** Further information on test methodologies and results is contained in the official Technical Report, a copy of which may be made available on request.