In a nutshell, Real Ale is brewed to rules setout in the 1970s by CAMRA (Campaign For Real Ale) which results in a few traditional styles, whereas Craft Beer has no restrictions which allows for more styles, ingredients and experimentation.
Real Ale Vs Craft Beer
REAL ALEReal Ale can only be brewed with traditional ingredients, water, malted barley, hops and yeast. It is unpasturised and unfiltered. It has two fermentations, the first takes place during the brewing process and the second in the cask or bottle. No gas is added to the beer so it can be flatter and would be served at around 13 degrees.
CRAFT BEERCraft Beers are brewed to emphasise creativity and unique tastes without contraints. They are usually unpasturised and unfiltered giving the beer a hazy appearence. They are carbonated and gas is used to dispense the beer which results in more fizz. Best served and drunk at around 6 degrees so the flavours change as the beer warms up.
What both camps have in common is that they both want to create a product with taste, as opposed to the mass produced fizzy brown water that the large brewers will have us believe is the 'best in the world, probably'.