Off Flavors in IPA.. HELP!

Hello brew folks!


The last few IPAs I have brewed have all had the same problem. They seem to taste fine, but there is a strange "off" aroma. This aroma is hard to describe. It is sort of a sweet aroma, that is also somewhat grassy and metallic, maybe a bit fruity (ester). Again, the beer seems to taste just fine on the palate, but the aroma throws it off. Usually the beer tastes/smells fine before putting it into the keg, but once it is carbed up, I notice the off aroma.. The aroma is fairly subtle; the beer still seems to be drinkable, just a bit off. I know it is really hard to get a good idea of what the problem might be from just a description, so I plan on taking a sample into my LHBS to have them taste it.

I generally only get this off aroma when dry hopping, which is why I feel that this is causing the issue. And although I think this off aroma is likely due to dry hopping, it is possible that something in my grain bill (or mash procedure) is contributing to this aroma (or perhaps fermentation problems). My sanitation procedures are good and I am doubting that it is infection, although it is possible (no visible signs of infection).

I am fermenting in a freezer with a thermowell and temperature controller. I fermented this IPA between 60-64F for 1 week, then after fermentation appeared to be mostly done, transferred to a secondary to dry hop for 10 days with 4 oz of cascade pellets (dry hopped at 60F). I made a 1300 mL yeast starter and pitched when the wort had reached 68F. For having 4 oz of dry hops, the hop aroma is definitely lacking too. I made sure to let the yeast settle out and dry hopped in the secondary, because I know that the yeast cells can metabolize hop oils and reduce the hop aroma. I added 2 oz of dry hops for the first 5 days, then added another 2 oz for an additional 5 days (10 day dry hop in total).

I mashed at about 156 F for 40 minutes. Mash temperature is also something I am considering, but I mashed my previous IPA at 152 F and it still had the same off aroma. Commonly, this is the grain bill I use for IPA:

12 lb 2-row pale malt
1 lb LIGHT Munich Malt
1 lb Crystal 15 L
0.25 lb white wheat malt

Maybe it is diacetyl? It doesn't really smell like butter/butterscotch, but I am thinking maybe this has something to do with it. I always do a diacetyl rest on my lagers, but not usually on my ales. I figure that fermenting at 64F should be high enough to drive off any diacetyl, but perhaps I am wrong. I am brewing with a 3-tier system and fly sparging. I have calibrated all of my thermometers and they are accurate.. This IPA started with an OG of about 1.064 and ended at 1.017. Also, the only method that I use to aerate my wort is by rocking/agitating the carboy before I pitch the yeast (maybe O2 would help, but again my other beers turn out fine).

I am tasting this beer today after carbing in the keg for 1 week. It is mostly carbonated, and a little young, so perhaps the off aroma will fade with a little more conditioning. In the past, however, this same off aroma persisted even after 2 months of conditioning.

Thanks in advance for any advice!

First thing that comes to mind is the short primary time. I would leave it on the yeast cake until the hydrometer samples are fairly clear of CO2. CO2 leaving solution can scrub hop aromas. This would increase the risk of oxidation in the secondary because of the minimal CO2 in the headspace.

Options to consider.
Two weeks primary time and rack to secondary while CO2 is still in the hydrometer samples. Dry hop for a maximum of 6 days to avoid the possibility of grassy flavors.

Leave the beer on the yeast cake for three weeks and dry hop in the primary.

I can tell you where the grassy nose is coming from...its how long you're dry hopping for. i suggest dry hopping no more than 7days max. I dry hop with around 2 oz's for 5 days and another oz for the last 2 days then carb and its perfect everytime.

The perceived sweetness can be coming from several places. It is probably coming for your really high 1.017 FG combined with the Munich and C15 taking up to 15% of your grist. I get a bready, sweet flavor from Munich. It could be due to lack of hop bitterness not balancing the perceived sweetness, but you didn't list the hop additions.

If you want to cut out the sweetness, my best advice would be to add around 5-10% of sugar and mash around 149-150F. This will give you easily close to 80% attenuation, which would get you down to 1.012ish FG. The 5-10% of grist refers to the extract, not the sugar weight. For example, you'll get 100% efficiency with sugar around 36-42 ppg depending on the moisture content of the sugar, so you'll want around 0.76 - 0.90# sugar added to the boil and remove some of your base malt to obtain the same 1.064 OG.

I'd reduce the Munich and C15 to no more than 5% each for a total of less than 10% of the grist. I'd remove the white wheat because you're going to have enough head retention from the high amount of isohumulones from the hops in this beer as well as the proteins in the other malts.

The grassy taste is probably coming from the long dry hop time. This does not sound like a diacetyl issue. Finally, the sweetness could be oxidation because IPAs have a tendency to turn sweet really quickly, but I feel this is the least likely sweetness source.

I have used shorter dry hopping periods in the past and still had the same problem, but I think we may be onto something here. I think that I definitely need to let it ferment in the primary for 2 weeks (as suggested) before transferring to the secondary and adding dry hops, and also I think I should decrease the length of the dry hop period to 5 days or less.

The off aroma is kind of harsh.. I would describe it as more "sweet" or "fruity" than grassy.. But there is definitely a bit of grassy flavor there (not a lot).. The aroma seems like something you would get from high fermentation temps, but this definitely isn't an issue.

Getting frustrated with IPA and think I might give up on it for a while (gonna brew a pilsner next).. The last 3 batches of IPA I have brewed were mediocre at best. I brew a lot of IPA because it is by far my favorite and I reason that brewing the same style will give me more "experience" with that style and it will therefore get better and better.. But wasting $30-40 a batch (as well as time invested) is just so disappointing and I am getting really frustrated . Someone told me they ditched dry hopping because of similar problems, but still achieve great hop aroma by adding COPIOUS amounts of hops at flame out. I really really REALLY love a huge hop aroma in an IPA, so I do large flame out additions AND dry hop.. But my IPA still lacks in hop aroma. Oh well I'm sure I will get it figured out. :rockin:

The sweetness is more of an aroma thing than a flavor issue.. But it does make sense that I may be using too much munich/crystal malt.

Also, you hit the nail on the head.. I did a 90 min boil and started adding hops with 30 mins left in the boil. There is a decent bitterness, but I agree that I am probably too light on the bitterness and too heavy on the malt flavor/aroma.

Here is the hop schedule I used:

30 min - 1 oz Simcoe (whole)
20 min - 1 oz Cascade (pellet)
15 min - 0.50 oz Simcoe (whole)
Flameout - 1 oz Willamette (whole), 1 oz centennial (whole), 0.5 oz Simcoe (whole) 3 oz cascade (pellets)

I was going for more of a "balanced" bitterness, and I have heard people have had really good results by doing all hop additions within the last 30 minutes of the boil.

Here's the problem: Late addition hops have very low utilization rates of converting alpha-acids into iso-AAs. 30 minute additions is somewhere near 5-10% where 60 minutes is 25% and 90 minutes somewhere in the 30% range.

From your additions assuming 14% AA Simcoe and 5% AA Cascade, I calculate roughly 30 IBU by hand. You can plug it into a a hop calculator with your actual %AA and get the correct answer, but that's why it's sweet. You have a pale ale level hop bitterness with a BU:GU of less than 0.5. You can do late hop additions for bitterness with all additions with less than 20-30 minutes in the boil, but you have to crank up the amount to account for the poorer utilization.

The munich malt gives a sweet aroma. Ever had a doppelbock? Those can be close to 100% munich and give a very rich, melanoidin, even sweet nose. I'd recommend dropping the munich altogether and then trying it with just a simple 85-5-10 with 85% 2-row, 5% C15, and 10% sugar with at least 45-50 IBU.

What kind of yeast?

What was your water profile?

Also you don't have to primary for 2 weeks. The last IPA i did was only a 2 week fermentation. i let it go for 9 days then dry hopped +5 days and cold crashed @ 14 days and kegged on the 15th day. Went grain to glass (fully carbed) in 21 days. I used wlp001 and fermented @ 65. the day before dry hopping i set the temp to 70 so the beer temp could raise to that over the dry hop period.

Beersmith calculated this hop schedule/bill to produce around 75 IBU.. But I do agree that it is probably far off from that (doesn't taste that high at all). I will definitely add a 60 minute hop addition to the next batch!

I love the flavor/aroma of munich malt. But it does indeed seem very plausible that it is the culprit here. I do like IPAs that are dry (Pliny).. But I also like IPAs that have balance (not too dry, not too sweet) and have a nice malt backbone. In the past my beers have lacked malt flavor and have been too dry.. Which is why I have been trying higher mash temps.

Do you think it is possible to get a good malt flavor/balance when mashing at 150F and adding sugar? Or do you prefer your IPAs on the drier side?

j1n said:

What kind of yeast?

What was your water profile?

Also you don't have to primary for 2 weeks. The last IPA i did was only a 2 week fermentation. i let it go for 9 days then dry hopped +5 days and cold crashed @ 14 days and kegged on the 15th day. Went grain to glass (fully carbed) in 21 days. I used wlp001 and fermented @ 65. the day before dry hopping i set the temp to 70 so the beer temp could raise to that over the dry hop period.

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I used WLP001 yeast. Our water here in Portland, OR is fairly soft (not a lot of minerals), and I filter it which removes any chlorine flavor. Yeah after waiting for 7 days the primary fermentation looked to be mostly done. It is interesting that you dry hopped at 70F.. Maybe this was part of my problem (I dry hopped at 60F and never let it get over 64F)..

You used a lot of whole leaf hops which are less efficient for bittering than pellet hops. just thought id mention that.

Brewtus_Maximus said:

I used WLP001 yeast. Our water here in Portland, OR is fairly soft (not a lot of minerals), and I filter it which removes any chlorine flavor. Yeah after waiting for 7 days the primary fermentation looked to be mostly done. It is interesting that you dry hopped at 70F.. Maybe this was part of my problem (I dry hopped at 60F and never let it get over 64F)..

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Hard water is better for IPAs. that may be another reason for it being less bitter than anticipated. next time add some gypsum to the water.

I like beers on the dry side. I also didn't calculate any type of flameout hops, so if you kept the flameout hops in for any length of time, you're going to get more bitterness. Consider first wort hopping, by adding an 1/2 - 1 oz of hops into your first runnings prior to boiling, you also get a very smooth bitterness from this technique.

If you don't want to add the sugar, just lower back down to 150-152F to get a more fermentable wort profile. 1.017 is a very high finishing gravity for an IPA, like barelywine/doppelbock ranges.

After reading the IPA article on the homepage of HBT, I'm going to take half of my flame out hops and do a hop steep for 15-20 min after i cool the wort down to around 180-190. I'm hoping it gives a boost in hop flavor and aroma. You might want to try that.

Cascade hops can have a grassy flavor and thats a fair amount you used, with some sitting for ten days. Try a different hop, do it for less time. Sweetness could be from higher mash temp. I think you also said you hit 60f while fermenting which "could" create some off flavor.

I actually like the "sweetness" behind the hops but it must be balanced. 60 minute addition is necessary to achieve this. First wort hops help with hop flavor too. My AIPA's are medium body with a sweet background, yet balanced, dry and hop forward with a lingering hop flavor.

An IBU/SG ratio tool is good to use for this.

https://www.homebrewtalk.com/f13/ibu-sg-ratios-style-129765/

That's a list of ratios from dividing your IBU's by the last two numbers of your specific gravity.

dbkdev said:

Cascade hops can have a grassy flavor and thats a fair amount you used, with some sitting for ten days. Try a different hop, do it for less time. Sweetness could be from higher mash temp. I think you also said you hit 60f while fermenting which "could" create some off flavor.

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I set my temp controller to 64F and the temp was between 60-64F during primary fermentation.. 60F or less in the secondary..

The desired range of WLP001 is 68-73F.. So I was thinking that 55-60 F might be too low.. I'm sure it would still ferment at this temperature, but usually I try to stick with the manufacturers recommendation.. I've fermented ales at 60-65 F with no off flavors though. A previous thought of mine was that maybe I didn't let the beer get warm enough for a proper diacetyl rest.

I absolutely LOVE cascade hops.. Next time I will try a different strain.. Maybe Amarillo or Citra.. I've tried using combinations of dry hops in the past, and I've found that "simpler is usually better"... When using multiple dry hops sometimes it just ends up as a cluster **** of flavors and sometimes one hop will dominate the rest (simcoe for example)..

tootal said:

I actually like the "sweetness" behind the hops but it must be balanced. 60 minute addition is necessary to achieve this. First wort hops help with hop flavor too. My AIPA's are medium body with a sweet background, yet balanced, dry and hop forward with a lingering hop flavor.

An IBU/SG ratio tool is good to use for this.

https://www.homebrewtalk.com/f13/ibu-sg-ratios-style-129765/

That's a list of ratios from dividing your IBU's by the last two numbers of your specific gravity.

Click to expand...

Thanks for the link!! I am definitely going to try first wort hopping on my next IPA. I am also going to change my grain bill, and lower the mash temp to 150F..

Here is what I am thinking for the grain bill:

12.5 lb 2 row pale malt
0.75 lb C-30
0.50 lb Carapils

I've always received the most aroma from dry hopping.. And with suggestions and thoughts I think I know what I might be doing wrong:

Too much dry hop for too long.. In the past I have achieved "weak" hop aroma with 2-3 ounces for only 6 days, which is why I increased the amount of hops and the length. But I think that this weakness from my dry hopping is due to several factors.. I've found that dry hopping in secondary works the best because yeast cells drag the aromatic compounds out of the beer with them (or metabolize them). So I am thinking I should cold crash in the primary, before transferring to the secondary for dry hopping, to help remove most of the yeast. Also, because more hop compounds are soluble at warmer temperatures, I think it would be best NOT to cold crash the secondary before transferring to the keg (more hop compounds probably precipitate). Furthermore, I am only going to use 2-3 ounces for dry hopping, and only for 5 days or so. I have given thought to dry hopping in the keg to avoid possibility of oxidation during the transfer to secondary, but I really don't like to use hop socks for some reason, it just weirds me out. I am also going to switch to using mostly pellet hops in the boil.. I've found that pellet hops provide a lot more aroma for dry hopping, so it makes sense it should do the same in the boil (pellet hops have more surface area exposed to wort and therefore better extraction efficiency).


I tried this IPA again today, and the aroma is a bit better. I think that some of the off aroma I mentioned previously is due to sediment at the bottom of the keg (yeast & hop particles), which is clearing out a bit after pouring a few pints. It has only been in the keg for a week, so I think it will get a little better.. Still no where near the hop aroma I am looking for. But I think I know what I need to do now to get this problem fixed.


Wow that was a bit of a rant. I'm not drunk I swear!
Thanks again for all the input! :rockin:

Brewtus_Maximus said:

I set my temp controller to 64F and the temp was between 60-64F during primary fermentation.. 60F or less in the secondary..

The desired range of WLP001 is 68-73F.. So I was thinking that 55-60 F might be too low.. I'm sure it would still ferment at this temperature, but usually I try to stick with the manufacturers recommendation.. I've fermented ales at 60-65 F with no off flavors though. A previous thought of mine was that maybe I didn't let the beer get warm enough for a proper diacetyl rest.

I absolutely LOVE cascade hops.. Next time I will try a different strain.. Maybe Amarillo or Citra.. I've tried using combinations of dry hops in the past, and I've found that "simpler is usually better"... When using multiple dry hops sometimes it just ends up as a cluster **** of flavors and sometimes one hop will dominate the rest (simcoe for example)..

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Personally, I think 67 is the ideal temp for wlp001. Would never use it at 73. Wouldn't even do over 70. 60 is low.

The more I think about it, the more I am convinced it is diacetyl that I am smelling/tasting. The lack of hop aroma, I believe, is a separate issue entirely.

Like I was saying in my original post, the last 3 IPAs I've brewed have had this same sweet smell/aroma.. And in the process of fermenting all 3, I racked from primary to secondary after about 1 week. After a week, krausen has usually fallen and airlock activity is low, so it seems like it would be OK to transfer to secondary. But I was just reading some other threads that talk about diacetyl problems when you don't let the ale sit in primary for long enough. In addition to a primary that is too short, I am also fermenting these IPAs between 60-64F, while the yeast cleans up the diacetyl much better at higher temps such as 68-70F.

I think the combination of racking the beer too early from the primary and a fermentation temp of 60-64F are both causing the aroma problem. I've always heard that people say fermenting WLP001 in the lower 60s results in a really clean beer with very low ester production, which is why I usually shoot for this temperature. But I guess it is critical to let the beer warm up to 70F or so to reduce the diacetyl (doh!).

I always do a diacetyl rest on my lagers. Which again, makes sense as to why I am tasting it in my ales and not in them.

Now I really want someone at my LHBS to taste this to see if it is indeed diacetyl.

For your fermentation, using WLP001 (or the Wyeast/Safale equivalent) you want to hold it at about 64-66F for 2-3 days, then allow the temperature to rise freely up to about 70-72F, then keep it there until you hit FG.

As others have said, drop your mash temp down to the 148-152F range. Your FG at 1.017 is far too high for the style and is undoubtedly due to your high mash temperature. Mash around 150-152F and you should finish at 1.010 which is about right for an IPA.

WRT your grain bill, I'd keep it about the same. 1 or 2 pounds of either Munich or Vienna will add some good malty flavor to an IPA but won't make it sweet.

Also, unless you are using something like a corny keg for your secondary, skip the racking to secondary to dry hop. You are just *begging* to oxidize your beer during the transfer, and you're also probably going to skunk it if you rack into a clear carboy and it gets any sunlight on it. It sounds like you have a temperature controlled fermenter, so cold crash your fermenter then dry hop in your serving keg. Put your hops in a nice fine bag, suspend them in the cold beer for 3-4 days, remove the bag and serve!

Update...

In an attempt to remedy the diacetyl issue, I am going to let the keg sit for a few days at room temperature. Maybe the yeast can do a bit more clean up if the temp gets to 70 or so.

I also tossed a few ounces of cascades into a sanitized hop sock and added it to the keg to see if I can squeeze in some more hop aroma (it is lacking for sure). WE WILL SEE!!


Going to be brewing a German pilsner this weekend. Stoked!

More updates!

My attempt to remedy the off flavors with the IPA mentioned above were unsuccessful. I ended up dumping over half the keg...

The German pilsner I brewed turned out excellent -- very clean and crisp!

Just brewed a Citra session IPA and I think I have corrected my problems with off flavors.

Several suggestions given to me on this thread were helpful. The first, was mash temp.. I lowered my mash temp to around 150-152, which I know helped to reduce the "sweetness" I was perceiving when mashing at higher temps. The second suggestion mentioned here that helped was regarding the grain bill..

Citra Session IPA Grain Bill:

9.5 lb 2-row pale malt
0.3 lb Munich malt
0.5 lb Crystal 60 L

On this IPA I made sure that the specialty malts were no more than 8% of the grist, which also helped to reduce the sweetness.

The third, and one of the most important factors that helped to reduce off/sweet flavors in my IPA was increasing my primary fermentation time. I made a 1.2 L starter, aerated the wort well, and used yeast nutrient. Within 12 hrs of pitching I had a very active and vigorous fermentation. After 7 days the fermentation died down and the final gravity was close... BUT! I left it in the primary for a full 14 days before racking to dry hop. With my previous IPAs I was racking to the secondary for dry hopping once I had reached my final OG in the primary, which was usually around 6-7 days -- not enough time for the yeast to clean up! I thought that so many yeast cells would go along with the beer to the secondary that they would still be able to do their cleanup, but I guess this was not the case... I let my pilsner sit in primary for almost 4 weeks and I think this helped a great deal with making the beer taste clean (which it did!).

Furthermore, dry hopping in the secondary AFTER primary fermentation is finished helped this Citra IPA to obtain an intense hop aroma - much more so than dry hopping in the primary. HOORAY BEER!!

14 days is good. I don't even bother raising temp. Just stay at 65 for almost any yeast (including secondary and dry hop).

I haven't had good luck dry hopping cascades yet. Seems to have a sweet melon taste. I would try using something like Galaxy or Mosiac next time instead of Cascade.

Glad you got it sorted out.