One other thought Joe. Did you use warm/hot water? It won't have anything to do with holding temps steady but could influence how long the pit takes to come to up temp. I agree that all those butts would hold the temp down for a while. "
The meat will absorb a lot of heat energy, causing the cooker temp to drop significantly."
Some Temperature Spikes Are Normal.
Joe - good info.... Try calibrating them both in boiling water and/or ice water & see what sort of readings you get....
When you ck your thermometer, I recommend reading up on it
here. It's true water boils at 212*F at Sea Level, but given a diff baro pressure and elevation it will be different. (Thanks Bob)
Not using water and just a foiled pan is the recommendation when using a temp. controller.
If by chance your thinking that it adds "moisture" to the meat... it does not.
An hour to come up to temp. with eight butts and a full water bowl? That seems quick to me!
Water may not make the meat more moist, but it does add humidity to the smoking environment thru steam which produces a different BBQ then a dry environment. The AmazingRibs.com science advisor Dr. Greg Blonder says "If you want to increase humidity, and you do, fill the pan with those red lava rocks sold at garden stores, and then add the water, but don't cover the rocks. They are very porous so they act like sponges, and the large surface area pumps more moisture into the air. And don't let fat drip into the pan because it will quickly coat the surface and prevent evaporation."
Of course Harry Soo disagrees; "Don't use any water in the pan. Just cover the water pan with foil top and bottom. I foil it twice so I can remove the second layer after the cook and refoil it. That way, I don't have to clean my pan. Dry heat allows the bark to form faster on the meat. Once the bark forms, you can introduce moisture. I just spray water with a regular spray bottle to encourage bark formation after the initial crusting has begun. To test for properly formed bark, use your finger nail and scrape the meat surface. If the crust has formed, it will not come off when you gently scrape it with your fingernail. If the crust comes off, the bark has not set, so don't spray until it sets. Let it cook longer and check back in 15 minutes. When the bark is set, we then wrap the meat in foil for about an hour, take it out and let it dry a bit. We've won many awards with this technique."
I say try both and see which one you and your friends/family enjoys most.
