Super low efficiency

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

John Long

Well-Known Member
Joined
Jun 22, 2008
Messages
94
Reaction score
0
Location
Olympia, WA
So I put my new MLT to use! It worked very well but my efficiency sucked. I measured a gravity of 1.014 at 124 degrees... so 1.025ish. Supposed to be 1.060.

5# german munich
4# wheat
1# crystal 40
some rice hulls

Mashed in ~3.1 gallons water at 155 for 5 minutes then splashed some cold water in to make it about 149. Mashed for 1 hour. Sparged with 5 gallons of 190 degree water.

I'm thinking the sparge water cooled down to about 180 or so when I poured it into my HLT.

I kept about 2 inches of liquid on top of my grain bed at all times.

What else could have given me such low gravity?
 
I used to fly sparge, but because of low efficiency problems I switched to batch. I used to get around 50-60%, now I'm hitting low to mid 80's. I had dozens of people tell me it was my grain crush, but I didn't think that could be the issue since I bought it pre-crushed. Not something my LHBS crushed either. Crush, Temps, and Sparge are usually what it comes down to.

I found that when I was fly sparging, the longer I took, the better my efficiency was. I see the same thing with batch sparging. How long are you taking to sparge? Also, are you taking gravity readings of your runnings and not just your pre-boil?

Another thing it could be is just improper mixing in the kettle. Your first gallon or so is going to have a higher gravity that your last few. So...if you don't stir it all up, you may get a different reading.
 
This is my first fly sparge. I've always used batch sparging with my mini-mashes. I spent about 25 minutes sparging. I will try longer tomorrow.
 
First, is your mash tun setup for fly sparging? What is the separation medium (false bottom, manifold or braid)?

Is the wheat in your recipe malted or raw/flaked? Munich can convert itself but not much else, especially at 149F for only 60 minutes.
 
I installed a CPVC sparge system on my MLT. The separation is braided steel.

The wheat was flaked.

What do you mean by "munich can convert itself but not much else"?

I wasn't aware malts converted things by themselves, let alone other malts/adjuncts... ? I don't get it.
 
You've got to step back a minute and get a handle on how all grain brewing works. There's a link in my sig for an all grain primer but essentially, starch is converted to fermentable sugars by enzymes that are already present in grain. Some grains have more enzymatic power than others and some have none due to lack of malting or being highly kilned killing off enzymes. Munich has enough enzymes to convert the starch inside the munich. If you add a bunch more unmalted (flaked wheat for example) there's not enough enzyme present to covert the starch.

Also, stainless braid setups are not ideal for fly sparging since they encourage channeling.
 
As Bobby eluded to... in AG brewing there is more to it than water and grain sitting in it.

Mash PH will make a difference.

Diastic power of the mash will make a difference.

Temperature.

Time.

Crush.

False bottoms and properly constructed manifolds are GREAT for fly sparging because they drain the bottom of the grain bed more evenly.

Using a braid while fly sparging is like pouring water down the center of the mash straight to the spigot... most of your grain doesnt even get rinsed, only that directly above the braid. Fluid dynamics.

You will get it... but read Bobbys primer and some articles on equipment and techniques that best suit them.
 
Wow, alright. And here I thought I was just making porridge and draining it.

I'll read through all the links! Thanks!
 
slow, slow, slow slow, slow drain when you sparge. if it doesn't take you 40 minutes to sparge, you are doing it too fast. also, stir the grain bed several times during the main mash.
 
slow, slow, slow slow, slow drain when you sparge. if it doesn't take you 40 minutes to sparge, you are doing it too fast. also, stir the grain bed several times during the main mash.


Point is, he shouldnt be fly sparging...
 
I fly sparge with a braid and run an average of 80% efficiency. I run around an hour to sparge, sometimes a bit longer for bigger beers. It can be done. I think the problem in this case is that with the wheat being unmalted, the munich malt didn't have enough enzymes to convert the whole mash. Flaked wheat should be run pilsner malt and in lower proportion than malted wheat. Keep with it, I'm sure your next batch will be better. And remember to sparge slowly. In the end the extra time is definitely worth it.
 
it takes me around 30 minutes to batch sparge. I let it sit for 15 minutes after each water addition to let the grain bed settle.
 
What then, exactly happens during a slow sparge that makes it more efficient then a fast one? I would think that adding fresh 170 deg water would dissolve most of the sugars instantly after a good stir?
 
There are two explanations for higher efficiency in "slow" batch sparging. The first is that the crush is so coarse that it takes a while for sugary wort to diffuse from the endosperm into the surrounding water. The other is somewhat related in that crush would affect it, but it's the possibility that you were not 100% converted and the extended rest (even if you're calling it a sparge) is providing additional conversion.

I've tried waiting and it makes no difference whatsoever. I add the sparge water fast, stir for a minute or two, drain full speed. Sparging takes me about 12 minutes assuming I didn't flake and forget to start heating my sparge water soon enough.
 
I'll second the fast batch sparge technique. My lauter and sparge process is to drain off the first runnings, add the sparge water, stir it up "real good", and drain it full blast.

The key is that when I drain, I hold the end of the drain tube above the water level in the MLT and then open the valve to fill up the drain tube. Once the drain tube is full of liquor, I lower it into the kettle. This encourages quick, complete drainage. The whole process takes about 5 minutes.

I'm using a CPVC manifold in a cooler.
 
I'm using a homemade copper manifold. It's got some good size slots in it, just small enough so they don't let grains through. I've found that with my setup, if I go full blast, I get a stuck sparge...then I have to stir and wait for the bed to settle again. If I go slow, it gives the grains more time to convert, prevents channeling, and gives me higher efficiency in the end. I'm sure fast or slow works just fine...it all just depends on what equipment you're using.
 
Back
Top