Had a few batches lately that I was expecting to a have a big hop flavor and aroma presence but actually was more of a grassy or strange hop flavor. Has anyone else had this with late kettle additions? So far it has happened with 5 gal batches of a pale (stone clone from this forum) and also with a brown but less noticeably so. The hops used were Ahtanum and Centennial respectively and I think 1 oz at flameout with the pale and 2 oz with the brown. I have have good with late additions of other varieties such as simcoe, cascade, amarillo, and even brewers gold. Is it maybe the specific hop variety that can cause these flavors if used in large amounts, or anything else I could be doing wrong?
Also, a question on technique, when doing flame-out additions, how long are you folks leaving the hops in? I generally leave them in until I'm nearly chilled to pitching temp (immersion chiller). Maybe this is too long?
Thanks for any help.