Efficiency problem

[oxbow1]

Hello everyone, this is my first post so go easy on me! I think I did my due diligence searching the forums for a solution without finding it, so here goes.

I've been brewing extract and partial mash brews for a while now, and have recently started AG low-gravity ales (as easily managed by the equipment I have). I generally get efficiencies in the 50-66% range, which is disappointing. Today I brewed an English mild which resulted in brewhouse efficiency of 56%. Perhaps someone can see the step in my process / recipe that is causing such poor results?

Recipe:
5.5# Maris Otter
0.5# Crystal 60L
0.25# Chocolate
1oz Fuggles 5%AA (45 minute boil)
Very soft spring water (alkalinity<25, pH 6.4)

Mash was as follows, in a mesh bag in a pre-heated 5-gallon cylindrical cooler:
-- 7.8qt strike water at 171.6 degrees, resulting in initial mash temperature of 155.6 degrees. Stirred very well, covered, let rest for 70 minutes, stirring occasionally. Mash temp at the end of the rest had dropped to 147 degrees.
-- added 2qt boiling water, intended to be a mashout but only brought the overall temp to 161. Still, this doesn't seem like a huge issue for conversion efficiency. Stirred well, let rest 10 minutes.
-- drained entirely into kettle.
-- Added sparge water, 8qt at 170 degrees. Stirred very well, let rest 15 minutes. Stirred again.
-- drained into kettle, collecting ~3.75 gallons of wort. Did not squeeze the bag, but let it drain pretty thoroughly.

Normal 60 minute boil with hop addition, then chilled, put into fermenter with enough water to get to 5.5 gallons. OG @ 69 degrees = 1.024 (if I'm being generous - probably closer to 1.022).

It seems the usual culprit is grain crush, but from looking at images posted on these forums and discussing this with the folks at the LHBS the crush should be alright. (Regardless I'll crush finer next time, just to see what happens).

Could the water softness be the problem? I have not checked the mash pH, but since the efficiency has been low for a variety of ales (light and dark), it seems like there is some other consistent issue.

Any help is greatly appreciated!

 

[WayFrae]

I think your main issues are topping up with water (which will kill your efficiency) and not squeezing the bag (since you sparge this might not be a big deal, I do no sparge so squeezing is crucial). Also I think you should try having your LHBS run your grains through the mill twice to see if that will help.

I am not sure about the softness of the water, someone more experience will have to answer that.

 

[wilserbrewer]

Do you still have the spent grain, if so examine it closely for uncrushed kernels. There should be few to none.

If you find a large proportion of uncrushed grain you may have found your problem.

Topping up the kettle with water does not help, but should not have killed it that much I'm guessing.

Is your kettle only 5 gallons? Can you collect and boil more wort next time?




Wilserbrewer
Http://biabbags.webs.com/

 

[oxbow1]

Kettle is only 5 gallons. Attached is a picture of the spent grain. There are a few uncrushed grains in there, next time I'll just crush a lot more and see what happens. Thanks everyone!

 

[wilserbrewer]

There are a few uncrushed grains in there, next time I'll just crush a lot more and see what happens. Thanks everyone!

While it is difficult to tell from a photo, sometimes whole husks look like whole kernels.

IMO that looks like many more than a few uncrushed grains.

Better luck next time...cheers.


Wilserbrewer
Http://biabbags.webs.com/

 

[NTexBrewer]

Something is not right with your strike water temperature and your mash temperature. You have strike water at 171.6 and your mash was at 155.6. This is a temperature difference of which is a difference of 16 degrees. Normally the strike water is more in the range of 9 to 12 degrees above the mash temperature.

Also, this is a low gravity beer to begin with. My quick calculation shows that at 70% brewhouse efficiency the beer would be 1.033.

I would check that your thermometer is accurate. I would check that your hydrometer is reading 1.000 with RO or DI water, not tap water.

Also, I'm not sure what you are trying to do with mashing in at 1.25 lb/quart ratio and then adding more water later. BIAB you are mashing with maximum amount of water or reserving a gallon or so to do a dunk sparge.

http://www.simplebiabcalculator.com
With this calculator I put in your grains and hops. Not sure what your equipment is but I would mash with about 3.2 gallons of water and then do a dunk sparge with 1.4 gallons of water at 170 degrees. You can dunk sparge in your brew pot and then add the remaining wort from your cooler.

 

[jahdub]

You should increase your mash water to as much as you can fit in your 5 gallon kettle. Increasing the amount of solvent (water) in your mash should greatly increase the ability to extract maltose from the grain.