Espresso is a brewing method that forces pressurized hot water through a compressed coffee puck at high pressure to pull a 1-ounce "shot."
Ristretto is a shot of espresso prepared with an abbreviated extraction time – typically 15-20 seconds. A shorter pull equals a shorter shot.
When preparing a Long Shot (or Lungo), the pull time is extended to 35 to 40 seconds. A longer pull amounts to a larger shot.
SIZE
Traditional espresso has a volume of 1 ounce for a single shot. A Ristretto single shot is only ½ ounce, half the volume of espresso. And a Long Shot is typically about 2 ounces for a single shot.
FLAVOR
Compared with traditional espresso, Ristretto tastes more acidic and less bitter. By contrast, a Long Shot pulls in more bitterness — nuttiness, caramel, and chocolate tend to stand out.
CAFFEINE
A Long Shot has slightly more caffeine content than traditional espresso, given the prolonged extraction. And a Ristretto has marginally less.