I have seen the liquid margarine idea on several rib videos on YouTube. I agree with Larry that they aren't a very healthy choice, but I would be OK with using it as part of coating for ribs where, as Brian says, you really aren't consuming a whole lot of it. I have, however, used brown sugar, honey and regular butter with no issue.
FWIW - not much - I ditched
Smart Balance a few years ago and personally use
Land O Lakes butter & olive oil mix for toast, corn on the cob, etc. Butter, olive oil and salt - nothing more. Not organic and definitely not as good as
Kerrygold. I figure I am doing good with what this, but maybe someday I will try mixing better quality butter with olive oil to make my own homemade alternative

!
When I was in Germany, we had breakfast at the small hotel in Berlin where we stayed. I couldn't believe how good their butter tasted. I told our hostess that it was SO GOOD and definitely not like American butter!
p.s. This conversation did provoke me to purchase the roll of butcher paper (which went on sale briefly
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). While I will probably never be as careful as Larry is regarding aluminum, this does seem like a better plan. If I had to hold the ribs for a longer stretch after grilling I could see covering butcher paper wrapped ribs with an additional wrap of foil. But, like Larry points out, the aluminum wouldn't then be in contact with the food.