How consistent is US05 attenuation?

[urg8rb8]

I brewed th same recipe twice, got the same OG gravity from mashing around the same temperature but got two very different FG readings. The first one finished at 1.009 and the second one finished at 1.015.

Why such a big difference?

 

[schematix]

US-05 is pretty consistent in my experience.

"around" what temperature did you mash?

Did the grains come from the same bag? I.e. were they the same brand, type, lot, etc?

What are you doing for fermentation temp control?

How did you pitch the yeast? Freeball it, rehydrate it? Same pitching rate?

 

[urg8rb8]

US-05 is pretty consistent in my experience.

"around" what temperature did you mash?

Did the grains come from the same bag? I.e. were they the same brand, type, lot, etc?

What are you doing for fermentation temp control?

How did you pitch the yeast? Freeball it, rehydrate it? Same pitching rate?

I'd say around 152 for mashing? The grains were not from the same bag and they were brewed about a year apart.

As for fermentation, I have a temp controlled chest freezer. Temp was in the high 60s both times. I think, if I remember correctly, for the first time I made a yeast starter. The second time I just pitched the yeast from the packet.

Beersmith estimated a FG of 1.016, which matched the second iteration. I was expecting this the first time but the gravity just kept on dropping.

Let's say it was a mashing temp error, how low would I have to mash to get such a big difference in FG?

I like the beer it made the second time, it's definitely more full bodied. I'm just confused as to what is going on.

 

[schematix]

There are potentially a lot of variables at play here.

What was your OG?
What was your grain bill?
Are you cooler mashing?
How are you measuring mash temperature?

If i had to guess this all comes down to mash temp. For the batch that ended lower, you probably spent more time in the high 140s so you had more beta amylase activity. Mashing in >150F will kill off all the beta and typically give you a beer with much higher FG because alpha can't break down starch into short chains.

 

[urg8rb8]

There are potentially a lot of variables at play here.

What was your OG?
What was your grain bill?
Are you cooler mashing?
How are you measuring mash temperature?

If i had to guess this all comes down to mash temp. For the batch that ended lower, you probably spent more time in the high 140s so you had more beta amylase activity. Mashing in >150F will kill off all the beta and typically give you a beer with much higher FG because alpha can't break down starch into short chains.

OG both times were like 1.072 or so. Grain bill was 14lbs 2row and 11oz Crystal 60. May temp was measured with a thermometer probe and I mashed in an igloo cooler. Is the difference between high 140s and low 150s that much of a difference?

 

[schematix]

OG both times were like 1.072 or so. Grain bill was 14lbs 2row and 11oz Crystal 60. May temp was measured with a thermometer probe and I mashed in an igloo cooler. Is the difference between high 140s and low 150s that much of a difference?

Mash temps around 150 +/- a little are interesting. Beta amylase (which makes for a more fermentable beer) is pretty much gone at 150. Alpha amylase (which makes a sweeter beer) overlaps beta a little and is good up to the low 160s. So if you mash at 152 for example, you have all alpha and virtually no beta. Mash temp does not correspond linearly to attenuation. There is a time/temp relationship as well.

US-05 is an aggressive attenuator in my experience. If you give it a fermentable wort it will take very bit of it. I routinely do a 97% 2-row 3% crystal IPA (drinking now, mmmm) in the 1.065 range with US-05 and it always drops to the 1.010 range. Great for dry IPAs.

1.009 is pretty low though for 1.072. What are you using to measure gravity?

I still think you are looking at a root cause of mash temp being a little different from batch to batch.

Did you use same brand/type of base malt batch to batch?

 

[urg8rb8]

Mash temps around 150 +/- a little are interesting. Beta amylase (which makes for a more fermentable beer) is pretty much gone at 150. Alpha amylase (which makes a sweeter beer) overlaps beta a little and is good up to the low 160s. So if you mash at 152 for example, you have all alpha and virtually no beta. Mash temp does not correspond linearly to attenuation. There is a time/temp relationship as well.

US-05 is an aggressive attenuator in my experience. If you give it a fermentable wort it will take very bit of it. I routinely do a 97% 2-row 3% crystal IPA (drinking now, mmmm) in the 1.065 range with US-05 and it always drops to the 1.010 range. Great for dry IPAs.

1.009 is pretty low though for 1.072. What are you using to measure gravity?

I still think you are looking at a root cause of mash temp being a little different from batch to batch.

Did you use same brand/type of base malt batch to batch?

I use a hydrometer that appears to be accurate.

You're probably right about the mash temp. It's possible that I went a little low the first time making it attenuate more.

I really don't know what brand I used the first time so I'm guessing it's not the same.

Would you say attenuation is linear from 150 to 160F?

I used a lot of magnum, crystal and citra in this IPA for bittering, late addition, and dry hopping. With all that hop and "high" final gravity, the beer turned out to be a full bodied IPA citrus juice! [emoji1]

 

[dmtaylor]

US-05 is very consistent for me.

Was one beer dry hopped and the other not? Hops contain enzymes and can trigger more fermentation.

Mash temp of 140s will definitely dry out a beer as well compared to mid/upper 150s.

 

[schematix]

I assume you are using std LHBS $8 hydrometer that ranges from 0.980 - 1.120. Consider purchasing lab grade narrow range hydrometers ($30 ea) as a future investment. 2-3 of them will cover the normal brewing ranges. Not absolutely required but the cheapo hydrometers have pretty course accuracy while the lab grade ones will correct to less than a SG point.

There are differences in grain from year to year, variety to variety, and malster to malster that make a difference. Very complex subject and one of the reasons why its challenging to make the same beer back to back every time. There is a science to it but it's not straight forward. This could be a factor as well.

I don't personally have a lot of data about single infusion mashing between 150-160. I typically do a Hockhurz style step mash to get benefits of multiple temperatures. The few times i've done a single infusion mash at like 158 i know i had some cloying beers though.

Dry citrus juice is my preference, but make what you like. To me malt subdues hops so i aim dry as possible for hoppy styles. So for me i step through 144-148-151-162-171 to get great attenuation but still great body and foam.

 

[day_trippr]

Just gonna leave this here...

Cheers!

 

[urg8rb8]

US-05 is very consistent for me.

Was one beer dry hopped and the other not? Hops contain enzymes and can trigger more fermentation.

Mash temp of 140s will definitely dry out a beer as well compared to mid/upper 150s.

They were both dry hopped. The first one, that had more attention, was dry hopped in the fermenter. The second one was dry hopped in the keg.

 

[urg8rb8]

I assume you are using std LHBS $8 hydrometer that ranges from 0.980 - 1.120. Consider purchasing lab grade narrow range hydrometers ($30 ea) as a future investment. 2-3 of them will cover the normal brewing ranges. Not absolutely required but the cheapo hydrometers have pretty course accuracy while the lab grade ones will correct to less than a SG point.

There are differences in grain from year to year, variety to variety, and malster to malster that make a difference. Very complex subject and one of the reasons why its challenging to make the same beer back to back every time. There is a science to it but it's not straight forward. This could be a factor as well.

I don't personally have a lot of data about single infusion mashing between 150-160. I typically do a Hockhurz style step mash to get benefits of multiple temperatures. The few times i've done a single infusion mash at like 158 i know i had some cloying beers though.

Dry citrus juice is my preference, but make what you like. To me malt subdues hops so i aim dry as possible for hoppy styles. So for me i step through 144-148-151-162-171 to get great attenuation but still great body and foam.

I do have the "cheapo" hydrometer. I'll consider getting the more accurate one.

If I make this again for the third time, I will mash at like 148 or something and see how much it dries out. The dryness should accentuate the hops more.

Your mashing procedure is very involved!

 

[schematix]

Just gonna leave this here...

Cheers!

I've never seen that graphic before but that's actually pretty good. Not perfect but good. I do disagree with the 'brewers window' though. I think it should be called 'single infusion window'. There are a few more knobs to turn by stepping through the various temps.

 

[stevehaun]

Beta amylase (which makes for a more fermentable beer) is pretty much gone at 150. Alpha amylase (which makes a sweeter beer) overlaps beta a little and is good up to the low 160s. So if you mash at 152 for example, you have all alpha and virtually no beta. Mash temp does not correspond linearly to attenuation. There is a time/temp relationship as well.

schematix: I am not sure where you came up with this concept. Beta amylase denatures faster at 152 F than it does at 142 F but it is not "gone" at 150 F. Even at 160 F, beta amylase will take time to denature. Chemical reactions driven by enzymes will increase in rate as the temperature rises until the enzyme begins to denature.

 

[schematix]

“Becomes ineffective quickly” would have been better terminology.

 

[rmyurick]

Possible wild yeast infection in first batch?

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