Alex's forehead was full of sweat. He was on his 4th start of the night and he had already burned 3 of the same ingredient. Although they were easily acquirable ingredients, his heart still bled a little when he thought of them getting ruined.
But that was the life of an Alchemist. He was lucky enough to get the Alchemy God's Knowledge, however, the other Alchemists didn't get such an opportunity. So, they had to work hard to get these ingredients and then burn them while trying to learn something from them.
An alchemist that was successful had more burnt ingredients and more exploded cauldrons than one that failed.
So, Alex suck it up and started the process a fourth time. Fortunately, the last 3 tries weren't wasted at all. Thanks to them, he had come to learn of the correct temperature and the correct movement required to extract the most energy from the ingredients without burning it.