Bitter or Pale Ale?
There is some discrepancy regarding when pale ales and bitters could be considered separate styles. Some historians look back just 60 years or so, while others point to brewing records from about 150 years ago, when the product was referred to as “bitter ale.” The variance is minimal, or non-existent in some cases, and some would point to the manner of dispensing as the decisive factor. On draft, it would be a bitter; bottled, a pale ale.
This is not to say that bitters are not available in bottles, as many are. Brewers can make very similar beers and call one a bitter and one a pale ale.
What of a bottle-conditioned bitter? It is a live beer, on yeast, and naturally carbonated. Certainly a cask version would be different and evolve somewhat over its brief life span. These are simply additions to the mosaic of beerdom, which allows even a regular beer such as bitter some noble discussion. Such is the romance of simplicity and authenticity. It is best left to the purists to ascertain.
The Essence of Bitter
Like all traditional English ales, the very soul of bitter is malt. Robust in character, English pale ale malt is revered by brewers for its solid contribution to the wort and its ease of utilization. Slightly fuller in color than two-row or pilsner malt, pale ale malt has a palpable firmness that adds dimension to even the simplest of brews. As bitters run from gold-amber to full copper in color, an augmentation with specialty malts is in order. Lighter versions make use of minimal specialty malts, while darker ones rely on more, or simply small amounts of very dark malts. The color-enhancing malts are crystal on the light end of the spectrum to black malt on the high end. They contribute flavor, mouthfeel and nuance. A light to medium caramel memo is a bitter requisite. It is not unusual, and wholly acceptable, to include adjunct in the brew. Most commonly, flaked maize is used, but sugar is also employed.
Implicitly, a significant dose of bittering hops is the norm. To a hophead, it may seem a bit restrained, but the measure is not meant to dominate the beer, only to urge the balance toward hops. The hop character is classically British in the authentic versions, with East Kent Goldings or Fuggles the most utilized, with Target and Challenger less often. American ale hops are even gaining favor in some breweries. The impression should be one of a lingering herbal and drying bitterness, with minimal flavor and aroma. Cask versions get a bit of aromatic dry-hopping in the cask, but it imparts little flavor.
Were one to split hairs on the bitter versus pale ale debate, the main contention would be in the hop flavor and aroma. Most would agree that pale ale has more hop flavor and aroma, due to the destination of the brew. Those made for bottling, pale ale, can have no dry hopping but a late addition to the kettle. The hot wort imparts some hop flavor. As the addition is copious compared to cask versions, the aroma is more pronounced. This is not a steadfast contingency, so once again, debate if you like, but most certainly, enjoy. Another case could be made that bitter is marginally maltier.