The only way to keep potions from blowing up is to buy Alchemy Tech to level 3. If I don't have that level, then I only make the potion that is needed to solve a puzzle, and don't do any others until I have Tech Level 3.

You can keep dragging Jam to the food storage hut and get him to eat to build his health up, but it goes VERY slowly. You can also take a risk and have another scientist (they don't have to be master level) make up the potion that will restore health more quickly and have Jam drink it. BUT there's always a chance that potion will blow and then you'll have another weakened scientist.