niter in the pan

[11-Nick]

Since steel pans aren't scrubbed clean like SS pans, is niter even an issue with regular steel pans?

[sapman]

I think niter is an issue in any pan. Eventually it will build and cause burning.

[psparr]

Maybe someone will chime in about vinegar. Does it react to the steel?

[Big_Eddy]

Nitre is less of an issue when batch boiling. There isn't a specific area of the pan that is always at the optimum concentration to precipitate nitre, and each batch starts with fresh sap so some of the nitre from earlier batches dissolves back into the sap.
For the OPs 25-50 trees and weekly boils, nitre will likely not be a problem. After every boil or two, give the pan a good washing or scrub lightly with a green scrubby.

At the end of the season, leave a film of sugar in the pan and hang it high and dry. Before the start of the next season, give it a good wash and scrub it well. If needed, a stainless wire brush will loosen up stubborn bits.