Stand up a resealable, two gallon-size plastic bag in a large bowl to keep the bag upright. Pour in the beer. Do not seal bag. Allow beer to go flat. Scatter pepper, ginger and salt on a cutting board and chop the onion on it. Scrape up and add to the bag with mustard, molasses and olive oil.
Holding the top of the bag in one hand, squeeze bag with the other hand to mix marinade well. Add chicken parts, seal bag and tip bag to coat chicken. Chill, turning occasionally.
Using tongs, remove chicken to a grill heated to Medium. Seal bag and discard it with the marinade. Grill chicken until it is golden brown and registers 170 degrees on an instant thermometer. Complete the meal with cold deli salads and icy drinks.
Galley Tip: save a bottle, such as a soy sauce bottle, that shakes out liquid a few drops at a time. Wash it and fill with sherry to pass at the table to splash on black beans and rice, seafood chowder or shrimp bisque.