Consistent low OG with BS2 - where to look next?

I have been .004 -.005 low (1.050 instead of 1.055 on my last batch) on most of my brews since getting BS2.

I am hitting my temperatures, getting the proper volumes into the boil kettle, there is almost no wort left in either the mash tun or boil kettle when done. I have tried batch sparge in both two rinses and just one with no difference.

I use a Corona style mill and get a good crush.

I have the efficiency set for 70% and am getting in the 60's.

I can provide more info if needed.

Any ideas on where I should concentrate to improve?

"Good crush" can be a very subjective term. Don't completely rule that out as a source of efficiency problems.

However, I recently read a thread here that leads me to believe that BS2 calculates kettle losses in an unusual manner. I actually found that, on my last brew day, BS2 projected a 75% mash efficiency. I missed my target OG by .003 points, but 3 different online calculators all agreed that my efficiency was 74-75.5%. The only thing I can see is that I have a .75g kettle loss figured into my equipment - after the thread I read a few days agi, I plan to eliminate that loss from my equipment and scale my next recipe up by .75g and see what happens to my numbers. If you're using that loss value, that could be coming into play.

That's a tough one. There are so many factors where it could lie. If it is related to Beer Smith 2, then I would guess that either the ppg of the grain is not the same as you were using in previous versions, or that your actual processes loss doesn't match what is in Beer Smith.

If it's not the software, the number one efficiency killer I hear is crush. Second to that is sparge, then I hear mash temperature and time. You could check that your thermometer reads 212 in boiling water.

What are you getting for grain absorption? How about mash Ph?

Here is a blog post on measuring efficiency: (Although I bet you are measuring it right)
http://woodlandbrew.blogspot.com/2012/10/brew-house-efficiency.html

And one on thermometer accuracy:
http://woodlandbrew.blogspot.com/2012/10/mash-temperature-and-thermometers.html

WoodlandBrew said:

That's a tough one. There are so many factors where it could lie. If it is related to Beer Smith 2, then I would guess that either the ppg of the grain is not the same as you were using in previous versions, or that your actual processes loss doesn't match what is in Beer Smith.

If it's not the software, the number one efficiency killer I hear is crush. Second to that is sparge, then I hear mash temperature and time. You could check that your thermometer reads 212 in boiling water.

What are you getting for grain absorption? How about mash Ph?

Here is a blog post on measuring efficiency: (Although I bet you are measuring it right)
http://woodlandbrew.blogspot.com/2012/10/brew-house-efficiency.html

And one on thermometer accuracy:
http://woodlandbrew.blogspot.com/2012/10/mash-temperature-and-thermometers.html

Click to expand...

I will check my thermometers again but they have been accurate so far.
I don't think I can crush any better without getting total flour.
I end up with the right amount of wort so I think my grain absorption is set right.
I am not measuring my PH. I am under the impression that it is not necessary with batch sparging.
I am going off the calculation of efficiency given in BS2 and that I am getting a fairly consistent .005 less that the predicted OG.

The beers have been really good. But, I would still like to get closer to the predicted OG.

Making good beer is what counts but am right with you wanting to have all the numbers line up and make even better beer.

If you want to change Beer Smith to match what you are getting, then adjust the Efficiency until the predicted OG matches the real OG. Or you could adjust the ppg for the grains individually.

You're right that when doing a batch sparge if the pH is out of wack you are less likely to get tannin extractions than if you were doing a fly sparge. Unless you did four batch sparges, then you might have a problem. When there is very little dissolved sugar, the wort looses it's buffering capability and the pH of the water can significantly impact the pH of the wort. If the sparge is hot and the pH if off you will have tannin extraction.

The pH of the wort durring the mash might be an issue. Every brew I have made required a small pH adjustment to hit the correct pH. I haven't experimented much with pH impact on mash myself, but some others here have. The data I have seen makes me think it's important to get right.

kh54s10 said:

I will check my thermometers again but they have been accurate so far.
I don't think I can crush any better without getting total flour.
I end up with the right amount of wort so I think my grain absorption is set right.
I am not measuring my PH. I am under the impression that it is not necessary with batch sparging.
I am going off the calculation of efficiency given in BS2 and that I am getting a fairly consistent .005 less that the predicted OG.

The beers have been really good. But, I would still like to get closer to the predicted OG.

Click to expand...

I know it sounds counterintuitive, but you could be crushing too fine...

On my first crush when I got my mill, I crushed right around .030", and got what I considered pretty lousy efficiency (low to mid 60's). I asked the guys in my club for their input, and even emailed the guys at brewmasters warehouse to ask how they had their mill set up, since I had gotten low to mid 70's with their crush. Based on their input, in subsequent brew days, I wound up going with a slightly coarser grind (right around .039") and I'm hitting 73% to 75%.

stratslinger said:

I know it sounds counterintuitive, but you could be crushing too fine...

On my first crush when I got my mill, I crushed right around .030", and got what I considered pretty lousy efficiency (low to mid 60's). I asked the guys in my club for their input, and even emailed the guys at brewmasters warehouse to ask how they had their mill set up, since I had gotten low to mid 70's with their crush. Based on their input, in subsequent brew days, I wound up going with a slightly coarser grind (right around .039") and I'm hitting 73% to 75%.

Click to expand...

I have been on the forum for a year and a half now and this is the first time I have heard this.

Anyway I don't think the crush is that fine. Also using a Corona mill is more difficult to adjust to a specific spacing. I may try conditioning the grain.

I agree with you - it runs counter to everything I've read here, which is why I looked at the guys in my club cross eyed when they suggested it. But then the guy from brewmasters warehouse had the same recommendation, so I figured I'd try it, and I can't argue with the results... Of course, I also can't argue with the fact that adjusting a corona is a tougher matter than a roller mill. Definitely go with the conditioning though - at the very worst, it'll help keep your husks intact.