Much lower than expected O.G. after batch sparge

[WhistlerBrew]

Hello everyone,

This is my first post on here; hoping that one of you fine folks can find my error. I started a Christmas brew the night before last and was WAY off on my O.G. I used the same batch sparge process with my last brew and it worked perfectly, so trying to figure out what went wrong this time...

10.5 lbs Munich 10 deg
3.5 lbs Brown Malt
1.2 lbs Special B
0.35 lbs Chocolate

Expected O.G. ~ 1.075

-Mashed the grains at 67 deg C for one hour.
-Added about 5 L water at 85 deg C and vorlaufed. Raised temp in mash tun to about 72 deg C
-Opened spigot and drained mash tun into kettle.
-Added remaining volume of strike water (80 deg C) to mash tun.
-Stirred and vorlaufed ~3L water, let sit for 10 minutes. Temp was ~70 deg C.
-Opened spigot and filled kettle with runoff.
-Boiled for 90 minutes

My O.G. came out at 1.046. As I said, this is the EXACT process I used last time and everything turned out fine. How on earth could I have missed the mark by 30 points?

Thanks!

 

[tre9er]

Who crushed the grain? That plays a huge part in things.

 

[WhistlerBrew]

It was the LHBS; they used the same crusher they've used every other time I've bought grains from them.

 

[tre9er]

Myeah, but that doesn't mean they paid close attention to the result. I check and even sometimes adjust my crush every time I do it. Just saying it's possible the mill setting changed since last time.

 

[WhistlerBrew]

OK, thanks. Can the crush really make that much of a difference in O.G.? And can you see anything wrong with my procedures?

 

[Gartywood]

I think that all the suspicions of crush and LHBS's purposely doing poor milling to lower efficiencies to sell more grain is a lot bunk and way over scrutinized. I feel that the most difference crush alone will make (assuming that the grain is crushed) is a 10% efficiency drop. Your talking about 40% shy in OG. So unless half the grains weren't even cracked I have a hard time believing that to be the problem.

My recommendation is take gravity readings of your runnings. Also with a bigger beer like this maybe do two batch sparges.

 

[WhistlerBrew]

So if I'm getting really low gravity readings from my runnings, how do I correct for that before the boil?

 

[Golddiggie]

Something else that can seriously KILL your efficiency is not mixing well enough when you dough-in and leaving clumps. Make sure you get ALL the grain clumps/balls broken up before you let it rest... Good temperature control can also impact the mash. IF the grain is milled properly/well then it's really how good a job YOU did that's the wildcard.

I've only had ONE batch where I didn't mix well enough and had a serious efficiency hit (about a 30-40 point drop). I've never let that happen since (it was early in my all-grain brewing life).

 

[diS]

I dont think crushing can have that huge impact, if it looked right it I doubt it is the reason of mass lower OG.
Did you calibrated thermometer and hygrometer? Iodine test was negative?
Did you check pH?

This is great read about efficiency:
http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency

 

[sjbeerman]

Hello everyone,

This is my first post on here; hoping that one of you fine folks can find my error. I started a Christmas brew the night before last and was WAY off on my O.G. I used the same batch sparge process with my last brew and it worked perfectly, so trying to figure out what went wrong this time...

10.5 lbs Munich 10 deg
3.5 lbs Brown Malt
1.2 lbs Special B
0.35 lbs Chocolate

Expected O.G. ~ 1.075

-Mashed the grains at 67 deg C for one hour.
-Added about 5 L water at 85 deg C and vorlaufed. Raised temp in mash tun to about 72 deg C
-Opened spigot and drained mash tun into kettle.
-Added remaining volume of strike water (80 deg C) to mash tun.
-Stirred and vorlaufed ~3L water, let sit for 10 minutes. Temp was ~70 deg C.
-Opened spigot and filled kettle with runoff.
-Boiled for 90 minutes

My O.G. came out at 1.046. As I said, this is the EXACT process I used last time and everything turned out fine. How on earth could I have missed the mark by 30 points?

Thanks!

Just some comments on your process. Sorry, I have to convert everything to gallons and Fahrenheit first. You mashed at around 152-153F, but you didn't mention your grain to water ratio (qts/lb). It looks like you were trying to mash out, but you only got the temp to around 162F. If you were mashing out, you should aim for 168-170F. Personally, I don't mash out but instead just drain the first runnings then do a single batch sparge. What was the volume of your first runnings? What was the volume of your batch sparge water? What was the total volume collected? What was the final volume in the kettle after the boil? Is there any particular reason you boiled for 90 min instead of 60 min? Do you typically take a preboil gravity reading? If not, I would strongly advise doing that to allow corrections to be made to adjust the OG if you miss your efficiency. This can simply be done by adding some DME to the boil.

 

[tre9er]

Something else that can seriously KILL your efficiency is not mixing well enough when you dough-in and leaving clumps. Make sure you get ALL the grain clumps/balls broken up before you let it rest... Good temperature control can also impact the mash. IF the grain is milled properly/well then it's really how good a job YOU did that's the wildcard.

I've only had ONE batch where I didn't mix well enough and had a serious efficiency hit (about a 30-40 point drop). I've never let that happen since (it was early in my all-grain brewing life).

This too. I've found that no matter if I mash out or not, how many batch sparges I do, what temperature I sparge at, none of that matters as much as crush and stirring. I stir furiously with one hand while slowly, ever-so-slowly doughing-in with the other. In fact, if I can figure out how I'm going to design some sort of system that adds my grains for me, slowly, and a motorized mixer that acts like a giant kitchen mixer in my mash tun. I want total mixation