Pat,
I have had good luck by vacuum-bagging whole or ground beans using my Food-Saver. I don't think a Zip-Lock bag is really very airtight. Freezers tend to really dry things out if any air can get in the bag. Most coffee comes packaged in a bag with a valve in it so they are not really airtight. I have kept it frozen up to two months and it tasted fine.
I have had good luck by vacuum-bagging whole or ground beans using my Food-Saver. I don't think a Zip-Lock bag is really very airtight. Freezers tend to really dry things out if any air can get in the bag. Most coffee comes packaged in a bag with a valve in it so they are not really airtight. I have kept it frozen up to two months and it tasted fine.