Never traded growler for growler before and was curious as to how well they hold up during shipping? I know most I've bought say consume within 48 hours but shipping can take from two to five days cross country.
The only problem I ever experienced was leakage from a plastic cap. No issues as long as I've used metal caps. As it happens I'm packing 2 growlers right now, both with metal caps for their long journey west.
As long as the growler is sealed tightly immediately after the fill is done it should last more than the 48 hours suggested. I've had no problems drinking 7-10 day old growlers. Carbonation and freshness has never been an issue. Just make sure that caps on tight!!!
props to Alewatcher. Go to a hardware store and get plumbers tape. It holds so much better than any other tape, actually adheres to itself so a very tight sea. On a personal note, I have sent and received numerous growlers, just pack it probably and you will be all good. If you need some pointers, message me.
My biggest tips for shipping growlers are box within a box (making sure to wrap the box which contains the growler in a garbage bag or two) and using rubberized splicing tape (the tape that Biglobo referenced above). The box within a box gives you maximum protection for shipping a growler full of liquid, I typically like to use Sierra Nevada / Same Adams 12 pack boxes as they are small enough to tightly pack with shipping materials to absorb any kind of impact. Then I wrap that box in a couple of garbage bags to help a bit in case of minor leakage, and ship it in a larger box which is sufficiently stuffed with packing materials. The rubberized splicing tape creates a water tight seal (when done right) around the cap of a growler. Wrap it in the opposite direction that the cap screws on the growler so as not to loosen the seal. Its a bit pricey, but well worth it in the long run. Final tip for shipping out boxes that contain both bottles and a growler is to modify a 12 bottle styro shipper. By cutting out a space in the styrofoam bottom and top you can securely ship a growler and a couple of extras without a problem. A trading partner of mine started sending me boxes this way from Vermont, and we've sent the same box back and forth 4-5 times without issues. Hope these tips help and cheers!