Aluminum foil and heat

[compman]

Its been a while since I've been on the site, but I had this happen to me over the weekend so I thought I'd discuss it with you all.

I had a contest over the weekend. I had a hectic week and was trying to get too much done on Thursday evening and Friday morning/afternoon before I left for the contest. I got there late and scrambled to get everything set up and prepped. I ended up oversleeping and was 2 1/2 hours behind schedule.

I cook on a Liberty BBQ GC and a Backwoods G2 Chubby. I had 2 butts on the Liberty and a brisket on the BW. Since I'm behind schedule I had to wrap the butts when it was time to put the ribs on.. Normally the butts are either off or are getting close to being ready to come off. I use a Guru on both cookers, and both are set to 250. I had a Maverick set on the rack above the butts, and it was running about 25 degrees hotter before I wrapped the butts and added the ribs. When I put the wrapped butts back on my rib rack it shot up over 300! I dropped the Guru down to 225, but I was still running about 300 on the ribs. After about 2 hours the rib rack starts coming down to 250, which is where I needed it.

It wasn't until last night that it occurred to me that the heat had to be reflecting off of the foil and causing the rack above to run hotter. It reminded me of Meathead's video with Harry Soo. He was talking about how he would coat a new WSM with Crisco or something to reduce the thermodynamics. After 2 hours or so of the ribs dripping and the smoke the foil got the brown coating that must have reduced the heat reflective properties, which allowed the temperature above the foil to come down. So, I come to you all for solutions.

I wrap with the shiny part of the foil to the outside. Should I have the dull side on the outside? Would the shiny side make a difference against the meat?

What would happen if I coated the foil with Crisco? It would cook, but would it make the meat inside the foil get too hot? Would it help in diffusing the heat reflection?

I understand that the easy answer is stick to my normal timelines, and don't oversleep. However, that doesn't always happen, and I thought this was an interesting problem to figure out. It might also be helpful to others.

Thanks

[Jerod Broussard]

I've always heard to put shiny inside so you don't reflect/deflect as much heat. Wonder if docblonder has tested this.

[CandySueQ]

I hate it when I get off schedule! Adds a whole extra problem to competing. I cook on a single level and most always have the shiny side out. Can't say I've ever noticed what you describe. Could you have a problem with the Guru? It should control and compensate for foil or whatever.

[compman]

I don't think its a Guru problem. I'm talking about the level above the rack where I have the Guru probe placed. Its naturally going to get hotter the closer you get to the top, but this was a huge difference.

By the way, were you in Hammond over the weekend?

[CandySueQ]

Yes, I was in Hammond! Were you?

[CandySueQ]

On the Guru side, have you calibrated the probes? I had a 10 degree difference in the cooker temp side and that really thru me off.

[DeusDingo]

i would imagine the shiny side would only deflect things like infrared radiation, and the parts that actually will cook the meat, the rapidly vibrating air molecules which makes up the entirety of the indirect cooking side, would not be affected by a particular side of the foil. the air molecules will still be slamming into the foil, transferring energy and making the foil molecules vibrate and thus heat as well... please correct me if i am wrong

[Jerod Broussard]

That makes sense.

[Strat50]

We actually had a debate about this at the restaurant some time back, so, I looked it up. According to ALCOA, the manufacturer of Reynolds Wrap, which side is exposed or not is irrelevant. Shiny,or dull, has no meaningful effect on cooking properties. I was not yet convinced, so I continued researching. I came upon a "how its made" video on You Tube, which confirmed the info from ALCOA.

[HorseDoctor]

That's in concert with what I have heard. Makes no difference.

[broilking4]

I had read the same some time ago but couldn't remember a source. Thanks Strat5q

[docblonder]

It makes no difference at all. The matte finished side still reflects around 90% of the radiation, but not uniformly, so it doesn't look shiny. But it still reflects as much as the shiny side, which is more like a mirror.

As the food cooks, sometimes smoke begins to stick to the foil, and this will affect how much IR it absorbs. I have some special black aluminum foil, and the effect is pretty strong. You can read about black foil near the bottom of http://www.genuineideas.com/Articles...eedTaters.html

[Jerod Broussard]

Thanks doc!!

[BigBear]

Interesting article doc. I've always cooked my Idaho russets in a 450 degree electric oven for 60 minutes to achieve doneness. From the looks of your graph I could back off to 400 degrees and achieve the same desired result.