I don't get clumping. I use an adequate quality pasta (De Cecco mostly), stir it when I put it in the water, and a few times after that, cooking to al dente. If I'm making a Caccio e Pepe or Carbonara I cook the spaghetti or (my preference) Buccatini I'm aiming for the minimum amount of liquid left, ideally just enough to put in the sauce. I use a frying pan so I can lay the noods out flat to minimise the water.
As I said I don't get clumping, it is absolutely possible to cook noods in minimal water without clumping because I do it so try switching some thing up if it's happening to you.
How do you stir long pasta in minimal water before it has softened?
While small pasta shapes are relatively easy to stir such that they break contact with anything nearby right from the beginning, long pasta tends to move together when stirring until they’ve softened - at which point they’ve already started sticking together.
You can try to stir it so that the pasta isn’t all running parallel before it softens, but then you get ends start sticking out of the water until it softens more, leading to uneven cooking.
For long pastas, I’ve found using more water and just adding a little flour while cooking to be a lot easier.
I use kitchen tongs to pick up and jostle the noods as another commentator mentions. It starts out parallel as you say. Flour would add a flavour I didn't want and I don't have an issue with uneven cooking or clumping so I don't need to.
shrug then go with De Cecco, it's still better than Barilla. But if you find a Molisana or especially a Garofalo, do grab a pack and taste the difference.
I'll pick up a pack if I see it. The top quality the supermarket we go to has is Rummo, it's the next step up from De Cecco (in the supermarket at least) and I buy it sometimes, but to me there's not a hell of a lot of difference between the two for the price difference.
As I said I don't get clumping, it is absolutely possible to cook noods in minimal water without clumping because I do it so try switching some thing up if it's happening to you.