Why is my cheese sauce gritty? Sometimes when making a very simple cheese sauce (butter, flour, milk, cheese [cheddar, usually]), the final sauce has a sort of gritty or slightly pebbly texture (rather than smooth) - it seems like maybe the cheese hasn't totally melted, even if I continue to heat the sauce.

Why does this happen? How can I avoid it?
Could be an unfinished roux (the butter, flour mixture). But most likely it's because the cheese was heated too quickly or too much, causing the protein to clump up.

Suggestions:


Melt with less heat
Use a double boiler (to reduce hot spots within the pan)
Toss the shredded cheddar with cornstarch first (starch helps reduce clumping)
Add cheese in smaller batches (easier to maintain correct heat level and stir cheese in)