I just made a pot roast tonight...it's just about done. I used a 12 oz. chuck roast (I cut up a big roast for smaller dinners). Anyways, all this about veggie moisture content has me interested and gaining experience. I used my 1.5 qt. glass covered oval casserole dish which I am really liking cooking with.
Next time, I'm going to start with bigger sized vegetables with my slow cook pot roast dinner. By the time the 1.5-2 hour cooking time is up, my smaller cut up potatoes, celery, onions, and carrots get rather reduced in size and lose a lot of texture (they become a bit mushy too). I'm going to start with much bigger pieces of vegetables next time. I now realize why they show bigger chunks of vegetables in pictures of pot roasts. Next pot roast, I'm going to put in an onion quartered and not broken up. Same with the potatoes. I'll not halve them. Same with the carrots and celery...they're small size reduced quite a bit and got mushy by the end of the cook time. Also, I know I can thicken the juices after cook time for the gravy effect (from all the water now gathered in the dish) but I'm still surprised how much liquid is given off by the vegetables during cooking.
Ideally tho, I'd rather not add in my potatoes and other veggies after the initial cooking time starts. I like the set and forget method of putting it all together, placing it in the oven and walking away 'till it's done.