With different types of cheese available, how do you select one that is perfect to make the best grilled cheese sandwich? A video uploaded on Youtube gives information about cheese making as well as the scientific explanation behind it.

Reactions, a Youtube video series from the American Chemical Society, posted a three-minute video about the scientific explanation of how cheese melts. The video aimed to answer why some cheese easily melt while others result into a “nasty mess.” Moreover, they gave a scientific advice in order to achieve the best grilled cheese.

So how does one get that perfect, gooey, melted cheese?

According to the video, the first step of cheese making involves forming curds out of milk. Milk has casein proteins which form molecular clumps called micelles. These negatively charged micelles bounce away from each other and are held by calcium. The video mentioned that calcium is important in making the perfect grilled cheese.

When the bacteria and enzyme is added, it converts lactose into lactic acid. This results to a drop in the PH level and causes the micelles to stick together. Consumerist noted that micelles create chains which trap water and result “into a mess of cheesy goo.”

The longer the time the cheese is put to age, more lactose is converted to lactic acid which lowers the PH level. The low PH level causes more proteins to break out from the micelles and “interact with fat and moisture in the cheese.”

The American Chemical Society’s video noted the importance of the low PH level in getting that perfect grilled cheese. But if it’s too low, it would still be a cheese disaster. Thus, they recommend cheese with a PH level between pH 5.3 — 5.5 such as gouda, gruyére or manchego.

If you find yourself torn between choosing a mild or sharp cheddar cheese, the video suggests to choose the mild one because it has better texture when heated.

Watch the full video here: