Originally Posted by jamursch
I'm pasteurizing my limes to juice and zest right now. Do they normally change color like this?
You can't use these for zest...by boiling them you have extracted most of the usable flavor. When I zest a lime, I scrub them in the sink to remove excess dirt...as Mystic stated...the boiling process of your wort will kill any bacteria...so scrub in the sink and use a whatever method you choose to remove the green portion of the lime skin, leaving behind the white portion of the skin (undesirable flavor).
Now if you were going to make your own limeade, you would wash the limes, juice them add a cup of water and bring to a quick boil, mix in your sugar and then add the rest of your water(cold) to get to the proper portion (add more sugar if necessary).