High attenuation

[Ridenour64]

Hey guys. Made a Dortmunder a few weeks back.
12 lb Pilsner
1.5 lb Munich
6.5 gallons to the fermenter
I mashed at 149, but I BIAB - no recirculating - I don’t even cover so I surely lost several degrees.
OG 1.056
FG 1.006
Yeast: WLP830
Brewfather estimated 1.012 as a FG. 1.006 is 88.8 apparent attenuation
White labs has the attenuation range 74-79

Is it common, or normal for attenuation to be this significantly higher, or could there be something else at play? I made a saison 2 batches ago that dropped to 1.002. Im pretty meticulous about cleaning and sanitation though. I checked my FG 3 days apart so I know it’s stable. Also, refractometer was used for all readings. I did use an adjustment calculator and I’m fairly certain it’s an accurate reading. I don’t have a hydrometer to check.

 

[day_trippr]

Well there's always the chance that some bugs are in play, but leaving contamination out of the equation, that grain bill was highly convertible into short length sugars to begin with (munich is much more a base malt than a specialty malt), and then you had the mash on the high-attenuation side of the temperature curve from the start. I'm not surprised at the apparent outcome...

Cheers!

 

[RM-MN]

I mashed at 149, but I BIAB - no recirculating - I don’t even cover so I surely lost several degrees.

Several degrees during the mash period or several degrees while conversion was working. With a good milling of the grain the conversion can happen rather quickly.

 

[Vale71]

Several degrees during the mash period or several degrees while conversion was working. With a good milling of the grain the conversion can happen rather quickly.

That's true but on the other hand enzymes don't stop working as soon as conversion is complete which means fermentability will still be influenced by the whole mash schedule. All we know so far is the temperature he mashed at, we don't know if it was held for 20 minutes or 1 hour and if mashout was performed.

 

[Ridenour64]

My mash was for 1 hour. I’ve heard the arguments for quick conversion but I’m
gonna stick with one hour, or longer.

This was in my basement which has an ambient of like 76. Really it would have only lost a few degrees over that hour.

I guess what I’m really asking is if the 74-79 attenuation range is just an average? Just surprised that my FG shot that low. Really, I’m not even upset with it. I’ll take the extra boost in ABV - just curious is all.

 

[MikeCo]

The specified attenuation is just an average. It is very dependent on mash temperature and the fermentables used. For example, recipes with a lot of simple sugars mashed at low temperatures can show higher than specified attenuation.