Looks like I spoke too soon, both the Tripel and the Grapefruit IPA are well and truly fermenting! The Tripel is almost constantly popping the airlock, maybe 3 or 4 seconds between rapports, and the IPA not far behind with 4 – 6 seconds between emissions.
The IPA has evidence of some foam touching the inside of the FV lid, and there’s a slight trace of bubbliness in the airlock, but no residue. The real star performer is the Tripel, which has managed to climb all the way up the side of the bucket and touched the lid, despite being only a third filled. Can’t imagine what this would have looked like in a 10 litre FV – probably time for a new carpet. Will need to keep an eye on these two.