When you say "wrinkled" does it look like tiny ripples on the surface of water just suddenly froze or does it look like teeny tiny bubbles and grey or white hardened foam on the surface? It sounds to me what I call "mechanical devitrification" I know that is not really a term but it appears like devitrification although it is caused as others have said by manipulating the glass while it is too cool. It should not have much to do with ambient temperature although your piece will cool down quicker obviously if it is cold in your studio.
Try an experiment, heat a section of glass up until you think it is hot enough to bend, twist or manipulate in some way. Instead of manipulating it, take quite a bit more time adding heat to the same area then manipulate it a bit. Just once and then pop it in the kiln.
Next, take an identical piece, some color, shape, size and heat it up until it is barely able to move, manipulate it in the same manner as the first piece but do so knowing it doesn't have quite enough heat then pop it in tbe kiln.
After they have cooled, compare the two. If the piece that you gave extra heat to is smooth and the piece you did not heat enough has that "wrinkled" appearance you are talking about, then you know that you need to add heat before you manipulate your glass. Going back over the glass with the flame in areas you have heated and manipulated will also help to melt in the mechanical devit.
Otter
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