Can Fresh Aluminum Beer Cans with Full Aperture Lids - 16.9 oz - Case of 207Aluminum cans offer 100% protection from UV and other wavelengths of light that are harmful to beer. There's still great debate surrounding whether cans or bottles are better at keeping beer fresh, but if done correctly, cans are theoretically the superior option. When a crown cap is crimped onto a bottle, the lining of the cap can form an imperfect seal on the bottle, allowing small amounts of oxygen in, as well as small amounts of CO2 out. Over time