Yeah, veggies really need to be cooked around 180 to soften and mellow. I was thinking about maybe baking a head of garlic and separating out the cloves and freezing them. Then they'd be ready to pop in. Meat has a lot of enzymes at work breaking it down (decaying it etc) but veggies not so much.

Hey, could you add some cool water to your bath? You could always take out some of the hot and add some cold. Stir it a bit. Or take your pot off the burner for a while.

But it seems like 140 is a pretty good temperature for a roast, maybe even a little higher.