Author Topic: Trying to determine source of off flavor  (Read 1276 times)

Offline James

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Trying to determine source of off flavor
« on: October 11, 2018, 03:42:22 PM »
So several, but not all, of last few batches have come out with a similar off flavor, and I am trying to determine what caused it. The flavor is to me a green sort of grass flavor.

From what I have found online the closest thing I can find that would cause this is improperly stored hops. I keep my hops vacuum sealed and in a freezer when not being used. I have read that they should stay good for a fairly long time. The hops I used were in the freezer ranging from around a year for one batch to a month or so in another. So I am not sure that is the issue.

I had another thought, but can't seem to find any information on rather it would cause such an issue. I did a yeast starter for all the batches, and just let it sit on the stir plate at room temperature, and it being Texas summer that temp may have hit the high 80s during some days. Could that cause an off flavor like this?

I'm planning a brew day for next Weekend, and going to rebrew one of the recipes, but stick the stir plate in my fermentation fridge, and see if that fixes it, but was wondering if anyone had an insight about off flavors from too high of starter temps.

Also if anyone has any other suggestions as to what would cause it I appreciate it.

Offline hopfenundmalz

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Re: Trying to determine source of off flavor
« Reply #1 on: October 11, 2018, 04:06:40 PM »
If there is a club in your area, see if you can get an experienced brewer to taste it and give recommendations.
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Offline Robert

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Re: Trying to determine source of off flavor
« Reply #2 on: October 11, 2018, 04:45:23 PM »
What are the recipes for the "grassy" batches?  That might help us identify a likely cause.
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Offline Richard

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Re: Trying to determine source of off flavor
« Reply #3 on: October 11, 2018, 09:34:49 PM »
Do you pitch the whole starter? If you cold crash it for a couple of days, decant the liquid and only pitch the slurry then any effects of high temperature fermentation should be minimized.
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Offline James

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Re: Trying to determine source of off flavor
« Reply #4 on: October 12, 2018, 03:27:22 PM »
hopfenundmalz,

I am planning on bringing a few samples to my clubs meeting this weekend for just that reason, but thought I would throw it out here as well.

Robert,
One was a Marzen, Jamil's recipe from Brewing Classic Styles, one was the Can You Brew It Arrogant Bastard Clone, and one was a Celis Pale Bock clone from Austin Homebrew. In the mix as well I brewed my Pale Ale recipe, with no problems, and my Hefeweizen with no problem.

Richard,
I do pitch the whole starter. I thought about decanting, but I thought part of the idea of a starter was to pitch active yeast and thought cold crashing would negate that, but I guess I could crash, decant and then maybe add a bit of wort in on the brew day to get it active again. 

Offline denny

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Re: Trying to determine source of off flavor
« Reply #5 on: October 12, 2018, 04:24:04 PM »
hopfenundmalz,

I am planning on bringing a few samples to my clubs meeting this weekend for just that reason, but thought I would throw it out here as well.

Robert,
One was a Marzen, Jamil's recipe from Brewing Classic Styles, one was the Can You Brew It Arrogant Bastard Clone, and one was a Celis Pale Bock clone from Austin Homebrew. In the mix as well I brewed my Pale Ale recipe, with no problems, and my Hefeweizen with no problem.

Richard,
I do pitch the whole starter. I thought about decanting, but I thought part of the idea of a starter was to pitch active yeast and thought cold crashing would negate that, but I guess I could crash, decant and then maybe add a bit of wort in on the brew day to get it active again.

While crashing your starter is worth a try, I haven't found any problems from pitching the whole thing.  How big a starter did you do?
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Offline klickitat jim

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Re: Trying to determine source of off flavor
« Reply #6 on: October 13, 2018, 01:28:28 AM »
hopfenundmalz,

I am planning on bringing a few samples to my clubs meeting this weekend for just that reason, but thought I would throw it out here as well.

Robert,
One was a Marzen, Jamil's recipe from Brewing Classic Styles, one was the Can You Brew It Arrogant Bastard Clone, and one was a Celis Pale Bock clone from Austin Homebrew. In the mix as well I brewed my Pale Ale recipe, with no problems, and my Hefeweizen with no problem.

Richard,
I do pitch the whole starter. I thought about decanting, but I thought part of the idea of a starter was to pitch active yeast and thought cold crashing would negate that, but I guess I could crash, decant and then maybe add a bit of wort in on the brew day to get it active again.
Pitching a whole starter... if you let it completely run its course, exposed to oxygen or air, then its oxidized and the yeast are done so there's no value to keeping the oxidized wort. If the starter has not run its complete course and the yeast are active and in suspension, its probably not terribly oxidized, and since the wort is full of active yeast in suspension, there is value to keeping/pitching the whole thing.

I wish we could have two separate terms for the two different methods, then we could know what each other is talking about. I make my starters the morning of brew day and pitch them that evening. The whole thing. It would be foolish to treat my starters the way a person would if they were simply using their starters to multiply yeast cells by allowing them to complete their life cycle and drop out of suspension. Conversely, why would they want to dump flavorless oxidized wort into their beer?

In short, we call both methods a starter, but both do not have the same purpose or the same results

Offline Richard

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Re: Trying to determine source of off flavor
« Reply #7 on: October 13, 2018, 01:32:13 AM »
Pitching a large starter that was fermented at high temperature could cause some off flavors, but probably not grassy ones. That does sound more like something from the hops, or stale grain.
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Offline Robert

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Re: Trying to determine source of off flavor
« Reply #8 on: October 13, 2018, 12:26:34 PM »
hopfenundmalz,

I am planning on bringing a few samples to my clubs meeting this weekend for just that reason, but thought I would throw it out here as well.

Robert,
One was a Marzen, Jamil's recipe from Brewing Classic Styles, one was the Can You Brew It Arrogant Bastard Clone, and one was a Celis Pale Bock clone from Austin Homebrew. In the mix as well I brewed my Pale Ale recipe, with no problems, and my Hefeweizen with no problem.

Richard,
I do pitch the whole starter. I thought about decanting, but I thought part of the idea of a starter was to pitch active yeast and thought cold crashing would negate that, but I guess I could crash, decant and then maybe add a bit of wort in on the brew day to get it active again.
Pitching a whole starter... if you let it completely run its course, exposed to oxygen or air, then its oxidized and the yeast are done so there's no value to keeping the oxidized wort. If the starter has not run its complete course and the yeast are active and in suspension, its probably not terribly oxidized, and since the wort is full of active yeast in suspension, there is value to keeping/pitching the whole thing.

I wish we could have two separate terms for the two different methods, then we could know what each other is talking about.
I make my starters the morning of brew day and pitch them that evening. The whole thing. It would be foolish to treat my starters the way a person would if they were simply using their starters to multiply yeast cells by allowing them to complete their life cycle and drop out of suspension. Conversely, why would they want to dump flavorless oxidized wort into their beer?

In short, we call both methods a starter, but both do not have the same purpose or the same results
Jim, you already solved this elsewhere.  An active one like you do is a "starter," because you're just getting the yeast awake and going.  One that's completed and decanted is "propagation,"  because you're growing up a new supply of cells, no longer active, which need to start up again when pitched.  (What I do, and what I call it.)  All that's left is to popularize the use of these preexisting, perfectly sensible terms. Start a movement.  Or propagate one, either way.
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Offline Richard

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Re: Trying to determine source of off flavor
« Reply #9 on: October 13, 2018, 04:44:07 PM »
Jim, you already solved this elsewhere.  An active one like you do is a "starter," because you're just getting the yeast awake and going.  One that's completed and decanted is "propagation,"  because you're growing up a new supply of cells, no longer active, which need to start up again when pitched.  (What I do, and what I call it.)  All that's left is to popularize the use of these preexisting, perfectly sensible terms. Start a movement.  Or propagate one, either way.

Sourdough bread makers have starters, too, and it usually refers to the sleeping culture. You warm it up and feed it, wait until it doubles, make bread with half of it and put the rest in the fridge. If someone looks in your fridge and asks you what that white goop is you say it is your sourdough starter.
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Offline James

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Re: Trying to determine source of off flavor
« Reply #10 on: October 13, 2018, 05:39:17 PM »
While crashing your starter is worth a try, I haven't found any problems from pitching the whole thing.  How big a starter did you do?

The Marzen was a 2 liter starter for a 10 gallon batch. The other 2 were 1 liter starters for 5 gallon batches.

I will usually get my starter going Wen. night for a Saturday brew. It stays on the stir plate until I'm ready to pitch.

I will try crashing and decanting on the next brew, and not change anything else.

Quote from: Richard
Pitching a large starter that was fermented at high temperature could cause some off flavors, but probably not grassy ones. That does sound more like something from the hops, or stale grain.

The grains I order fresh every batch from a homebrew store with good turn around, so I doubt that it's the grains. The hops are what I am fearing because I have a rather large stock of hops vacuum sealed and in my freezer, and would hate to have to throw them away. They have all smelled fine when I opened them, which from what I have read usually means they are still good.


Offline denny

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Re: Trying to determine source of off flavor
« Reply #11 on: October 13, 2018, 05:58:06 PM »

While crashing your starter is worth a try, I haven't found any problems from pitching the whole thing.  How big a starter did you do?

The Marzen was a 2 liter starter for a 10 gallon batch. The other 2 were 1 liter starters for 5 gallon batches.

I will usually get my starter going Wen. night for a Saturday brew. It stays on the stir plate until I'm ready to pitch.

I will try crashing and decanting on the next brew, and not change anything else.

Quote from: Richard
Pitching a large starter that was fermented at high temperature could cause some off flavors, but probably not grassy ones. That does sound more like something from the hops, or stale grain.

The grains I order fresh every batch from a homebrew store with good turn around, so I doubt that it's the grains. The hops are what I am fearing because I have a rather large stock of hops vacuum sealed and in my freezer, and would hate to have to throw them away. They have all smelled fine when I opened them, which from what I have read usually means they are still good.

Didn't realize you were using a stir plate.  You should definitely decant, then.  I stopped using my stir plate a couple years ago because I found it wasn't necessary.
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Offline Robert

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Re: Trying to determine source of off flavor
« Reply #12 on: October 13, 2018, 06:41:27 PM »
Jim, you already solved this elsewhere.  An active one like you do is a "starter," because you're just getting the yeast awake and going.  One that's completed and decanted is "propagation,"  because you're growing up a new supply of cells, no longer active, which need to start up again when pitched.  (What I do, and what I call it.)  All that's left is to popularize the use of these preexisting, perfectly sensible terms. Start a movement.  Or propagate one, either way.

Sourdough bread makers have starters, too, and it usually refers to the sleeping culture. You warm it up and feed it, wait until it doubles, make bread with half of it and put the rest in the fridge. If someone looks in your fridge and asks you what that white goop is you say it is your sourdough starter.
Thanks for reminding me, I have to feed that goop in the fridge tonight!  Anyway,  cars have "starters" too, but we can't analogize everything called a "starter."  With bread, the goals are also distinct from the two brewing procedures in question,  pure propagation and pure activation.   Sourdough is both.  Some homebrewers actually  do something like this.  But this just shows how fuzzy the language we use is, and how useful it would be, as Jim said, to have a way of clearly understanding what we're all talking about, since what's ideal procedure for one is not for the other.
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Offline denny

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Re: Trying to determine source of off flavor
« Reply #13 on: October 13, 2018, 06:51:35 PM »
I don't think the language is all that fuzzy until we murk it up.  Starters have always referred to cell propagation.  so let's not change that.  Let's find another word for "the other thing".
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Offline Robert

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Re: Trying to determine source of off flavor
« Reply #14 on: October 13, 2018, 07:12:21 PM »
I don't think the language is all that fuzzy until we murk it up.  Starters have always referred to cell propagation.  so let's not change that.  Let's find another word for "the other thing".
"Rousing?"   It's been used that way before.
Rob Stein
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