Can cheap vodka be used for cooking (with good results)? A friend left about half of a bottle of some questionable, admittedly very cheap plastic-bottle of 80-proof grain vodka at my house. I should have remembered the name, but I'll edit it in when I get home if need be. Anyway, I don't drink very often, but have a few recipes in mind, so I just want to know if A) low-quality vodka will lead to the same culinary results as, say, a low-quality wine, and B) is there anything I can try to see whether or not this particular bottle is suitable? In case you're wondering, I'm looking to make my grandfather's borscht recipe and some hazelnut liqueur (for baking and occasionally adding to coffee).
Also, I did read this answer, and like the... ah... answerer, I suspect that any differences in this vodka have something to do with it being at the very bottom of the price range.
EDIT : Both the borscht and liqueur came out great. At first I thought the liqueur was far too harsh, but it seems that letting it sit for a few days after filtering let it smooth out.
Cheaper spirits can certainly be used in culinary applications. The results won't be identical, but inexpensive liquors are a lot more cost-effective since the subtle differences in flavor between middling and quality spirits tend to get masked by other flavors. This is especially true when you're applying heat, which will burn off much of the alcohol (though not all) and change some of the volatile flavor compounds in the spirit. For things like a tomato sauce made with wine, a pan sauce deglazed with brandy, or a dessert flambeed with rum, the difference between bottom-shelf and high-end product will be evident only in the cost.

Poor-quality vodka will have some "rough" flavors if you're drinking it straight, and those might carry over into the liqueur in particular. Chilling will help, so you probably won't notice much difference in your borscht, and once you bake the liqueur into something I doubt any flavor difference will be noticeable in the final product. As a rule of thumb, the more you manipulate the spirit, the less you'll notice its provenance.

I can say confidently that using free, leftover plonk in a culinary application will be a much better use than drinking it!