How to prevent pasta from sticking

① Use a large amount of hot water (at least 10 times the weight of the pasta)
This is because the starch exuded from the pasta is sufficiently diluted, and the pasta cooks evenly without sticking together.

② Do not use hard water (*Tap water in Japan is soft water)
It is believed that using hard water (alkaline containing calcium ions and magnesium ions) causes a lot of starch to ooze out and the noodles to stick together easily.
Tap water is often made alkaline (pH 6.8 to 8.1 in Japan) to prevent corrosion of water pipes, so when boiling pasta, add some acid (lemon juice, tartar, citric acid) to adjust the pH. should be around 6, which is weakly acidic

③ Pasta will start to stick together in the process of gelatinizing starch in hot water for 1 to 2 minutes after starting to boil. Keep stirring at this time to prevent the pasta from sticking. (Stir occasionally after 3 minutes)
Gelatinization temperature of various starches

④ Add 1-2 spoons of oil to the boiling water.
At this time, put the noodles in and out several times to cover the surface of the noodles with oil.
(* Regarding this, there are books that argue that it is meaningless because oil floats on water.)
⑤ Add salt
In addition to seasoning, it suppresses gelatinization of starch, reduces seepage, and reduces sticking of noodles.
(*Some people say that there is little effect because the amount of salt is small compared to the amount of water.)

Also, as a way to prevent sticking after boiling
① Rinse the boiled pasta with hot water
Can remove gelatinized starch on the surface of pasta
Rinse boiled noodles with cold water

② Put olive oil on the pasta (entangle the butter)
If you don't use sauce, you can add olive oil to the boiled pasta to coat the pasta and prevent it from sticking.

The ideal way to boil the pasta is to use a large amount of boiling water so that the momentum of the water causes the pasta to convect. In other words, do not stir with chopsticks.
This is because the surface of the pasta is scraped off with chopsticks, etc., and the taste and the entanglement of the sauce are not uniform. (* This is a level that can be confirmed with an electron microscope.)