A. A phrase used before happy hour etc as we were leaving work before we got to the Pub. It means you are looking forward to your Beer, Beverage etc.
B. American Beers for the most part before the Craft beer craze were essentially tasteless Pilsners. Think Budweiser, Pabst, Miller and the list goes on. With the Craft Beer Craze that started occurring 20 plus years ago, bees started to have flavor again. You were getting Stouts, IPA, Weissen Beers etc.
So I can taste my beer means the beer has flavor.
Now the old joke about American Beers: How is having sex in a canoe like American Beer? It is F___ing close to water