Brewhouse efficiency disappointing

[Nostrildamus]

I hadn't calculated my brewhouse efficiency in a long time and had completely neglected it until my last 10 gallon batch. My LHBS proprietor always states what he thinks would should have to hit your Target OG (and it always seems a little high) and I've taken his word for it up till now and now looking back on it, there is definitely some inefficiencies in my system or in the crush which he provides. Let me give you my last recipe and procedure and maybe together we can nail down where I've gone wrong.

My system:

2 keggles MLT with a false bottom and SS spigot. Kettle with simply a SS spigot.

The recipe:

10 gallon batch:

18 lbs Pale Male (LHBS dude would say I should use 20-21 lbs here to get 1.050)
1 lb Flaked Barley
1 lb Biscuit

2 ozs Centennials
3 ozs Goldings

Procedure:

Mash for 60 mins @ 154 F 1 quart/pound ratio
Lauter and sparge for 75 - 80 mins

First runnings: 1.062
Final: 1.008 ( a little low and dangerous, I know)

11.5 gallons collected
10.5 gallon post boil volume with 1.042 gravity
Brewhouse efficiency: 63% (from my understanding)

So the possibilities are that I have miscalculated the potential gravity, miscalculated the brewhouse efficiency, mashed poorly, sparged and lautered too fast or have received a poor crush (I've heard this complaint about my LHBS before).

Wadda ya think?

 

[Tonedef131]

What is dangerous about 1.008 FG?

 

[Nostrildamus]

Tannin extraction from the husks

 

[farmbrewernw]

What is dangerous about 1.008 FG?

It can become dangerous if you are sparging too much, thus having the possibility to extract tannins. I'm no expert, but at some point in sparging you wont be extracting much sugar but there is the possibility to extract those nasty tannins from the husks, so with a final running of 1.008 you aren't extracting much in the way of sugars. I think most people on here try not to exceed three sparges to avoid tannin extraction.

EDIT Damn I got beat to it.

 

[Revvy]

Was that a mistyping of your water to grain ratio...1 quart/pound is a littke thick, imho...I usually use 1.25 quarts, that even what is recommended by my beersmith setup.

Here's what palmer has to say.

The grist/water ratio is another factor influencing the performance of the mash. A thinner mash of >2 quarts of water per pound of grain dilutes the relative concentration of the enzymes, slowing the conversion, but ultimately leads to a more fermentable mash because the enzymes are not inhibited by a high concentration of sugars. A stiff mash of <1.25 quarts of water per pound is better for protein breakdown, and results in a faster overall starch conversion, but the resultant sugars are less fermentable and will result in a sweeter, maltier beer. A thicker mash is more gentle to the enzymes because of the lower heat capacity of grain compared to water. A thick mash is better for multirest mashes because the enzymes are not denatured as quickly by a rise in temperature.

As always, time changes everything; it is the final factor in the mash. Starch conversion may be complete in only 30 minutes, so that during the remainder of a 60 minute mash, the brewer is working the mash conditions to produce the desired profile of wort sugars. Depending on the mash pH, water ratio and temperature, the time required to complete the mash can vary from under 30 minutes to over 90. At a higher temperature, a stiffer mash and a higher pH, the alpha amylase is favored and starch conversion will be complete in 30 minutes or less. Longer times at these conditions will allow the beta amylase time to breakdown more of the longer sugars into shorter ones, resulting in a more fermentable wort, but these alpha-favoring conditions are deactivating the beta; such a mash is self-limiting.

A compromise of all factors yields the standard mash conditions for most homebrewers: a mash ratio of about 1.5 quarts of water per pound grain, pH of 5.3, temperature of 150-155°F and a time of about one hour. These conditions yield a wort with a nice maltiness and good fermentability.

He calls for 1.5 quarts as a "difference" splitter.

 

[Nostrildamus]

True, I could use to up the water content of my mash. I'll keep that in mind as it is possible that the enzymes may not have had the chance to move around a get to the starches they needed to. That's something ingrained (no pun intended) from my past experience of multi-step mashes.

 

[Tonedef131]

Tannin extraction from the husks

I didn't realize he was talking about final sparge runnings, I thought that was his final gravity. I am retarted.

 

[ajf]

Your first runnings gravity seem suspiciously low. See https://www.homebrewtalk.com/showthread.php?t=73229&page=2 and read to at least post 16
There's nothing wrong with using 1 qt water per lb grain for the mash. I do it all the time. I have tried thinner mashes. They result in a more fermentable wort, but I couldn't detect any change in efficiency.

Have you calibrated your thermometer?
Have you calibrated your hydrometer/refractometer?
If using a refractometer, did you use brix/4 to get the SG, or use software or a more advanced formula to convert brix to SG?
If using a hydrometer, what temperature did you test at, and did you apply temperature correction?
How much dead space do you have in the MLT?
Do you use whole hops that soak up a lot of sugar rich wort?
Did you use an iodine test to check for complete conversion?
From your first runnings gravity, it looks as though you could have a mash problem (poor grain crush, poor pH, wrong temperature, inadequate mixing, inadequate calcium etc). An iodine test should indicate if this is true or not, but it is also worth checking for the sparge efficiency.
At the end of the sparge, if your grain is too dry to stir, add some more hot water (just enough so that you can stir the grain bed). Then stir the grain bed really well, and let rest for a couple of minutes. Drain off enough wort to completely flush out the outlet system, and then take a hydrometer/refractometer sample of what remains.
If these runnings have a higher gravity than your original final runnings, then you have channeling problems, and should slow down the sparge rate or modify the delivery mechanism.

Credits.
I wish to credit "Kaiser" for the fly sparge efficiency check. It's the only thing he's posted on the forum that I could understand.

-a.

 

[Slartiblarfast]

Do you mash out?
I've found that (upon suggestion from my LHBS dude) heating the mash before sparging makes the sugars less sticky and increases the final yield.
If I was making a five gallon batch from half your grain I'd expect a post-boil starting gravity of 1.060, at least.
My personal method is to remove a third or so from the mash when an iodine test shows conversion is mostly complete, bring it to a near boil, mix it back in, and start heating my sparge water.
Brought my efficiency from 60% up to 85%.
If you aren't doing something similar I'd highly suggest figuring out a way to bring your mash up to the same temp as your sparge water before washing the grain, it will increase your efficiency dramatically.

 

[Kauai_Kahuna]

I wish to credit "Kaiser" for the fly sparge efficiency check. It's the only thing he's posted on the forum that I could understand.
-a.

Hey - Knock off on Kaiser, I understood his video on detonation's, only because he had pictures, video, graphs and stuff... like that.

Truly - I think I have learn more "important" things here than I did in many years in a college. Ahh, my waste youth.