Your Garlic/onion issues is listed on my Beer flavor/odor wheel. Onion smells are listed as a sulfur component. Most sulfur issues in beer are either a yeast/fermentation issue or an Infection issue. I doubt its related to your hops but i suppose anything is possible. Id start looking for an infection in your cold side equipment and reexamine your fermentation time table/temps.
Not long enough for yeast to clean up fermentation byproducts. (H2S)
Fermentation temp to hot/cold (H2S)
Boil kettle being covered during boil (DMS)
What Yeasts are you using to ferment your IPA's? Ferm temps and how long in what vessel?
Are these beers in kegs? After some googling different sulfur issues ive read that you can force carb them and then burp the kegs to have the CO2 "carry" the unwanted smells out of your beer.
Good luck Man, hope it works out for you!
Jeff M, thanks for the insight. It's never a bad idea to review one's process when there's an issue.
I have been using 1056 or wlp090 for my APA/IPA. I ferment at 65-67f and raise the temperature to ~72 when fermentation activity begins to slow after about a week. It's held at this temperature for another 7-10 days to allow the yeast to fully attenuate and clean up. When it tastes right, I drop the temperature to 32f over a couple days and then add gelatin to clear for a couple days. The beer is then allowed to warm to 60+ and dry hops are added. After another 2-3 days it is kegged and slow-carbed for a week before serving.
I believe my sanitation is adequate. I only get this g/o issue with certain hops.
Burping the sulphur from keg is a good tip. I will try that.
Erockrph, I love the tangerine and onion rings with a side of asiago description for Summit. That's spot on for my experience with it. Although I have had very good commercial beers with Summit that were just tangerine with a hint of asiago and no onion.