Completely agree with Chris; I'd just like to add that ideally, you need two different loaves: a really fresh, premium one (Warburtons if poss) for hookbait and a slightly stale cheapie (at the "toast or discard") stage for mash. Trying to mash fresh bread gives a ghastly lumpy mess; trying to keep less-than-fresh bread on the hook will drive you mad.
Being broke and mean, I usually split a good loaf into bags of four or five slices and freeze them, each for a day's hookbait.
I think that a fresh, cheap loaf is best for "liquidising" in the blender, but I don't use it as much, so I'd be happy to learn otherwise. This is funny stuff: the harder you squeeze it (to throw), the more it floats before breaking up and sinking - so it's best delivered in a feeder or a pole cup "as is", or wet, in tiny balls, thrown in when fishing bread-punch for bits (a whole subject in itself).
As you're after bream, it's probably worth mentioning the value of "cocktail" baits - maggots, corn, white fishmeal boilies or whatever on the hook, with a veil of fluffy flake pinched on at the eye of the hook. Bream will whittle away at the bread, then take the goodie -and the hook - rather than leave a bare hook which they drop.
It's probably also worth mentioning a few things you can add to mashed bread -it's very versatile - DAMP bran helps it break down; brown crumb helps it bind for throwing, and gravel gets it on the deck pronto. Hemp pulls roach and chub, in particular, and "Brasem" and/or molasses pull(s) bream.
Experiment, enjoy, and ,please, report back!