we are fementing (look at me technical jargon already!) our first homebrew (from a kit :oops: ) in the plastic bucket provided, it is at a steady temp but the lid is starting to expand and bulge :shock: its only been fermenting for 1 day ... is this ok?
Lol, stop panicking.
How strong do you think the seal is on a snap-on plastic lid? If pressure built up that much, it would flip the lid up a bit at most, not explode the bucket. The bulge is a good sign and shows that things are on the go. Like someone said, lift a bit of the lid a little and smell, even listen, to a bit of pressure be released. In fact its as well to keep a little bit of the lid not quite closed fully to help prevent any bulging, not that it's a main problem. Everything will relax after a few days and the initial vigourous ferment will slow down. At this point you can snap the lid back down fully and just have a peek at it once a day.
The first few days when it's bubbling vigourously, you should also see quite a fair bit of froth or foam (a head of beer in fact) on the top of the mixture, and so much that it can in fact touch the underside of the lid. If it seems too vigourous and any froth likely to seep out the sides of the lid, just scoop off a handful or two (with a clean ladle) to lower the height of it. When the ferment has slowed, the froth tends to mostly disappear and you will then just have the dark beer colour (with an odd froth floater maybe) and the height of the mixture will be back to more or less what is was when you began. If any froth had touched the underside of the lid, it will now dry out as the level drops. I like to remove the lid at this point and give it a wash (just clean warm water should do it) to remove any residue. It only dries on more and becomes even harder to remove the longer you leave it. I don't like the idea of dried, crusty, stale beer foam lingering above the mix either. It's not a big deal as at this point you are not too far away from transfering from the bucket to bottles or a keg anyway, but all the same.
It's ok to have the lid off for 5 mins especially in the later stages. You can if you wish, cover the bucket with a clean towel (don't let it slip into the bucket) for any short time the lid is off.