Bread smelling and tasting beery

I Made 2 loaves using 2 packets of  bread mix. When starting to use the first  loaf everything was fine ,but after a few days the bread seemed less crispy when cutting and there was a slight beery smell but the taste seemed ok.The bread was 90% used for toast and lasted one week.Both loaves were each kept in a stayfresh bag.The second loaf was started today and tastes quite beery, it still feels quite fresh but am not sure whether this should be used.I hope some people can advise me on this and also if possible can tell me what is causing this beery taste.

Thanks