So - the last two beers I have brewed (one a 1.068 citra APA w/ munich and melanoiden, the other a 1.075 IPA with simcoe, amarillo, munich and crystal 40) have come out with a very strong ester aroma and flavor. I'm fairly certain I am dealing with esters - I detect a ripe apples / pear / general sweetness where there absolutely should not be. This is something I haven't experienced since my first homebrew, and I usually brew pale IPAs and APAs as my standard beers... Both beers were done by re-pitching US05 slurry to a ~1.3 L starter (used a calculator) - note: don't have stir plate, do intermittent shaking water treated to reach 0.5 Cl / SO4 ratio , mash pH of 5.2 (although I only calculated w/ software , did not measure actual pH ... I have about 120ppm alkalinity as CaCO3 eq so I do have to add PO4 acid mashing at 152 and 150 respectively 60 min boils, ~14 min chill time both dry hopped with 3oz / 6oz respectively both began fermentation at 64*, then bumped to 72* after four days spent 14 days in primary, checked gravity, bottled (both beers) The only theories I have so far are that my thermometer glitched during cooling (I use a hand held digital hach) and I actually pitched into 80* wort , but seems unlikely to happen twice... or that my temp controller probe is off and i'm actually fermenting way hotter than 72.. Anyone experience issues with esters? any thoughts on what else I could be doing wrong?
First of all let me say that I've never experienced this myself. Sounds like you have an ethyl acetate issue, though. Couple questions: which generation is this slurry? Have you calibrated your thermometer lately? If you pitched your yeast into hotter than normal wort, this is certainly a way to make your yeast throw off more esters, as most esters are formed during the log phase and increased temperature increases the amount of esters formed. Also, if you have used this slurry for multiple generations, you could have some genetic drift that is also responsible.
It seems your pitching temp and fermentation temp do not help here, you will need to age this batch a bit longer, there ´s no other way to try to diminish ester-fruity flavors.
I am uncertain what you mean by "glitched" here. Do you mean that for an instance it provided a false reading? I am unfamiliar with this 'failure mode'. Have you tested your thermometer? For example placed it in warm water and also used another thermometer (e.g., red liquid thermometer) to confirm it is operating properly? Cheers!
My thermometer does this funny thing from time to time where it will be slowly ticking downward while I'm chilling, then all of a sudden the digital display reads ten degrees less, I figure "woah , lets pull that chiller". It actually happened to me last night while cooling down wort for a starter, I took it out, let it settle to ambient, then put it back in and it read where it was a minute ago again. This could certainly be the culprit if my eyes aren't playing tricks on me.. Just a quirk of my thermometer - I will definitely watch for this in future, and calibrate to a known accurate unit ASAP. After doing some reading, it seems that some Oxidation off flavor characteristics seem similar to what I am experiencing - could it be that I am experiencing some oxidation? would it be noticeable only 4 weeks from brew day ? I don't feel I have a particularly Oxygen careless process, but I do not have the ability to do closed transfers...
I would suggest you purchase a new thermometer. The ultimate would be a Thermopen but I am happy with my Thermoworks RT301WA-N. It provides accurate and stable readings for me. http://www.thermoworks.com/RT301WA It is on sale now for 19 bucks. I have never read about oxidation caused flavors like you described in your OP. The oxidation flavor that seems popular to mention is a cardboard/papery flavor (it is the compound of trans-2-nonenal). When it comes to hoppy beers I would guess the first thing that would be noticed from oxidation would be hop aroma fade. Did you note that your hop aroma is not as expected? Given the beer styles you have brewed (APA/IPA) with the amounts of hops you used for dry hoping I am frankly surprised that you could detect ripe apples / pear with all of that hop aroma that should be present. Cheers!
@JackHorzempa - the hop aroma is there in full force, but the overwhelming sweetness of the esters is absolutely wrecking it at the moment. I'm so bummed this has happened twice in a row! I will leave these bottles in the cellar for a month or two and see if the flavor fades. I think new thermometer is in order for sure. I guess I'll brew a saison next
How long ago were these beer bottled? I have consistently noticed that my hoppy beers (i.e., IPAs) are best at sometime like 4-5 weeks after bottling day. The beers are carbonated at 2 weeks but they just do not taste 'right' at that point in time. They need another 2-3 weeks of conditioning to reach their peak of flavor. Me too! Sometime next week I will be brewing my annual Saison. Cheers!
This is second generation US05 Noted - Do you think that 72 is a bit high for US05? These have been in the bottles for 4 and 2 weeks respectively. The sweetness is so intense and so obvious that I have to think its more than just conditioning related. I have had lots of ales taste good, maybe not peak, but good around two weeks after bottling.
I have brewed with US-05 at 72 degrees (the temperature reading of the fermometer) many times without experiencing any issues. Given that the one batch is at 4 weeks post the bottling date this does seem to indicate that 'something' is amiss here other than needing some more conditioning time. Cheers!
In my experience with IPAs, "general sweetness" = oxidation. It is much easier to get oxidation under control by kegging. Indeed, a couple of bad oxidation experiences with IPAs is what finally drove me to keg. Cheers!
Interesting @utahbeerdude - any theories on why this would be a problem with IPA's exclusively? In some recent soul searching / researching I have decided that my pitching rate could be the culprit with these last two brews. I was re-pitching slurry, which includes a massive assumption about cell density. 1 billion ? 2 billion per ml ? Who knows? I have read that runaway ester production can be a problem in high gravity beers that are underpitched. I have since purchased a stir plate and flask and am abandoning the intermittent shake method... Kegs though. That will be the ticket once I can scrape together the dough. For now i'm going to pitch my beers at pro brewer rates and hope for the best. Cheers !
I don't know that it is exclusively an IPA thing, per se, but it is possibly the combination of a typical IPA malt bill, high hop dosage, and oxidation. Cheers!
