That's a lot of questions! I'll try to answer as many as I can. :-)
> How long can
> I store it in the fridge? If I want to freeze it, can I? And how do I do
> that, still in the liquid?
You can store it in the fridge for a week and in the freezer for 6 months
without the liquid. Just wrap each piece tightly in plastic wrap.
> And does that affect the cooking time/taste?
It should taste fine, and remember, it's already cooked. You're basically
just reheating it with a sauce when you add it to recipes.
> Also there is a recipe on the side of the box for Seitan burgers that
> involves cutting up the seitan and mixing it with onion, and oatmeal and
> stuff and cooking it in a pan. Is the seitan slice not good as a burger?
I think seitan is much more like roast beef than a burger. I use it sliced
with a gravy or with barbeque sauce to make sandwiches. To make it seem
burgerlike, I would think you'd need to mince it up like the package suggests,
though I've never done that. (I just buy Boca burgers when I want burgers.)
> Also when you see a recipe that calls for seitan can you use any form of
> seitan? I see all these interesting patties and slices and balls at the HFS,
> can I use these, or is that different from what I will be making from the
Generally, when a recipe calls for seitan, it means the unflavored kind that
you're making from a box (or from scratch, which is much harder and more time
consuming than using the mix, believe me). If what you see at the HFS is
plain seitan, not "turkey slices" or something that has been flavored to be
like meat, then you can use it. But it's a lot less expensive to use the mix
and the mix usually makes enough so that you can use it in your recipe and
still have some left over for sandwiches.
I hope this helps. Let me know if you have any more questions. Just thinking
about seitan has helped me figure out what I'm fixing for dinner tonight! :-)