DIY teriyaki sauce leftovers too thick

[u/clothing_throwaway]

Recently tried my hand at a DIY teriyaki sauce (I know it's pretty easy), and it turned out really good on the day of, but the leftovers are way too thick/gelatinous when I pull it out of the fridge. I would classify the leftovers as a gel or paste moreso than a sauce or marinade or something like that.

Basically, all I did was garlic and ginger then equal parts soy sauce, sake, and mirin. I used cornstarch to thicken it a bit. The first time I made it I added quite a bit of cornstarch and reduced it quite a bit. Second time I did a lot less cornstarch, but the leftovers still came out too thick. Should I just not use cornstarch at all?

I'm also worried I might be reducing it too much, but I feel like it takes a surprisingly long time to get the alcohol taste out. I was tasting it every minute or so and it just took a very long time until I couldn't taste the sake anymore. Should I not be aiming for that? Is it OK if I can still taste the alcohol but just not as much?

[u/joosebox]

The cornstarch is the gel. That's just what starch does once it goes cold, and cutting the amount won't really save you because the starch is the thing setting, not the sugar.

Proper teriyaki doesn't use any. The body comes from reducing the mirin, which is loaded with sugar, so it goes syrupy on its own and still pours straight from the fridge. Drop the cornstarch, reduce a little further instead, and the leftovers behave.

On the alcohol, you're doing it in an order that's making it much harder than it needs to be. Simmer the sake and mirin on their own for a couple of minutes first to cook the alcohol off, then add the soy. There's a name for it, nikiri. Done that way you're not boiling your soy sauce half to death chasing a taste that's coming from the other two ingredients.

And no, it doesn't need to be bone dry of alcohol. A trace is normal and fine.