Check out the last issue of Zymurgy. It has a couple good articles on milds
English Ordinary Bitter
Bitter & English Pale Ale
Category Number: 4A
Original Gravity: 1.030-1.038 SG
Color: 6.0-14.0 SRM
Final Gravity: 1.008-1.013 SG Bitterness: 20.0-40.0 IBU
Carbonation: 0.8-2.1 vols Alcohol by Volume: 3.00-3.80 %
Description: Lightest strength bitter. Originally kegged or casked and served by a hand pump without pressure. Traditionally served only a few days old from a cask and consumed within a day or two.
Profile: Mild form where malty flavor has a slight edge over the bitterness. Slightly dry with high attenuation. Light to medium body (taxed in UK by starting gravity). Gold to golden brown in color. Carbonation higher in bottled versions.
Ingredients: English malt, hops (Fuggles/Goldings) and ale yeast. Hard water with high calcium-sulfate (gypsum) content brings out bitterness.
Examples: Young's Bitter, Samuel Smith's Old Brewery Bitter, Fuller's Cheswick