O
- Oatmeal Stout
- A style of stout brewed with oatmeal. Oatmeal was used
for its nutritive qualities as well as its ability to impart fullness
of body and flavor.
Octoberfest
- A bottom-fermented Vienna- or marzen-style beer, originally
brewed for Germany's Oktoberfest celebration. Copper-colored, malty,
and sweet.
- Old Ale
- In Britain, a medium-strong dark ale most often consumed
in winter.
- Original Gravity
- The density of the wort prior to fermentation, expressed
as a ratio as compared to the density of water. A measure of the amount
of solids in the wort.
- Oxidation
- When a packaged beer is stored for a period of time, it stales, or oxidizes. Different beers stale at different rates and develop off flavors. The rate of oxidation goes up as the temperature goes up. Oxidation is familiar to drinkers as a papery or cardboard like character in both taste and aroma.