Complex sentence: The result, when the can is then poured out, is a surging mixture in the glass of very small gas bubbles and liquid, just as is the case with certain types of draught beer such as draught stouts.
Split into simpler sentences: The result, when the can is then poured out, is a surging mixture in the glass of very small gas bubbles and liquid. This is the case with certain types of draught beer such as draught stouts.