Just to add to Rita's comment. Alcohol, like caffeine is a known trigger for heart rhythm problems. Not everyone reacts, but those who do need to avoid them. However, alcohol related issues like a-fib are more likely triggered by excessive consumption. One beer may not have any significant effect. 4-5 may be beyond your tolerance level.
No mystery here. Alcohol has that effect on many. My daughter got married yesterday and I celebrated quite a lot. I woke up at 3 AM very tachy. I took my beta blocker early and drank a few glasses of water. It was much better this morning. Today I did notice more PVCs than I've been having, but I also forgot to take my fish oil today. We'll see if it was acting up because of the alcohol or if they've returned. Alcohol dehydrates you and when your blood volume decreases, your heart BP usually goes down, thus making your heart beat faster to pump against a lower systemic pressure to maintain your cardiac output. Try drinking some water in between each beer.