I had a very strange problem making nacho cheese sauce recently, and hope you can help me figure it out.
I started with a roux (about 2-2.5 tbls butter, 1.5 tbls gluten free AP flour), cooked it for a good 5 minutes on medium. Then I started adding half and half, about a 1/2 cup, then in went about a cup of milk. Everything was going well, smooth and clean looking.
Next I began adding cheese, pepper jack. I started with a pound, shredded. It seemed ok, so I let it cool in the pan (off heat) since we weren't ready for it yet. When I came back later, it acted fine, but tasted a bit floury. I'm known for oversensitive tastebuds so had my spouse taste it. He said it needed more cheese. Added another pound of pepper jack and a bit more 1/2 and 1/2. Now the floury taste seems REALLY pronounced to me, along with some ever-so-slight graininess on the tongue.
I can't believe it's an undercooked roux, I make roux-based gravies/sauces frequently, so I'm wondering if the milk broke (slight graininess) but wouldn't explain the initial floury taste, if it's a problem with the cheese (store-brand block) or something else. Any ideas? This is the 2nd time I've had nacho sauce fail recently. I'm at wits' end and ready to just buy the pre-made stuff from Costco.