Luncheon meat used to be the only real bait that we used to use, but now pellets and boilies are the main baits, which we've really found by trial and error as some anglers prefer to keep it as a big secret as to exactly what they are using. You can fish with 21mm and 14mm pellets on a hair, but drilling them can be a pain as they often split in two. One of my local tackle shops is now selling pre-drilled 14mm's, so I've bought a bag of those, whilst I have started to drill my own 21mm's using a 1.5mm drill bit in a cordless drill/driver with slow start. I haven't split too many so far and I'll probably end up drilling my own 14mm's too, because they have been drilled using what I think is a rather large bit. It seems that anything that is fishmeal or halibut flavoured works well. We have only recently started using the 3, 6 and 8mm pellets as loose feed, but they seem to be able to get the fish's head's down and get them grubbing around.
The above photo shows some of the additional pellets that we are using. The first bucket is the Elips barbel buster bucket with various sized pellets in it. I have drilled some of the largest pellets for hairing, which you can see in the tub below the bucket. I know that some people superglue their pellets to the hair rather than drilling them, but either way, they do break down quickly in the warmer waters of summer, and need checking every hour at the most. The other bucket is a mixture of betaine, halibut and elips pellets which I use in my big feeders. There are some smaller ones in these days to increase any scent trail as they hopefully fall out, rather than having too tightly packed a feeder, which may restrict the scent trail. Something else I will be trying, is the halibut boilies soaked in halibut oil. Before I soak them, I will be drilling them to allow the oil to penetrate deeper.
Something else a bit different is the Black Pepper Spam that some of the supermarkets are now selling. It may well have started as a limited edition, but is still available a year on, and has quite a kick to it over normal spam. If you like to feeder fish, then try a method mix in a standard cage and hair either sweetcorn or a piece of meat, its far better than normal plain crumb groundbait, and the barbel will follow a rolling feeder and attack it before its settled, if they are in the mood. One thing we certainly have found is that when the weathers hot, keep it simple. A few grains of sweetcorn can be far more deadly than any pellet or boilie and really can be the difference between something and nothing. When using sweetcorn, I tend to put about 4 or 5 grains on my standard length hair, loop it back onto the hook and put 1 or 2 grains then onto the hook to lock it in place. This way it doesn't look as suspicious as those anglers that have a straight line of grains behind their hook, and keeps all the grains closer to the hook so when they are picked up you should be guaranteed a better hook up.
If you like pastes, but don't know how to make them, then try this. For a really smelly cheesepaste use something like Danish Blue or Stilton, and white crumb groundbait. Grate the cheese and kneed the crumb in a bit at a time until its a firm dough, then roll it into boilies or leave it as a lump and stick it in the fridge or freezer until its needed. You can also add some salt to preserve it, and use any sort of cheese. For a trout pellet paste, buy the pellet powder and some eggs and make it up the same as the cheesepaste adding the powder to the egg. To turn your paste into shortlife boilies, simply roll the paste into balls and drop them into a pan of hot water for about three minutes. They will dissolve a little bit, but even if the egg doesn't cook all the way through, they do become firm enough to put on a hair-rig.