Please help. Horrible efficiency!

Ok everybody. Here's the deal. I brewed a beer two days ago that I thought would easily end up in the 1.080 range. It's a cross between the Midwest Power Pack Porter and Oatmeal Stout. They milled the grains, and I ran them through my newly built corona just for extra measure.



This is what I ended up with going into the fermenter. I mashed with close to 10 gallons at 164 to get the mash to 150. My thermometer seemed to be slow to read, and only got up to about 147. I mashed for about 80 minutes because I forgot to put the oats in for about 20 minutes. First running during fly sparging were 1.084. I sparged with 6 gallons at 170. I missed final runnings because it finished draining before I realized it. I had about 12 gallons at the start of the boil. I added the pound of brown sugar about 10 minutes before the end of the boil. I ended with 9.5 gallons in the fermenter at 1.068. According to that calculator, thats only about 55% efficiency into the fermenter. What gives?

 

I typically see efficiency's in the mid to upper 50's when targeting 1.075+ OG's, so this doesn't look too bad. Mash efficiency tends to go down pretty rapidly once OG's start getting high, thus hurting your overall efficiency. I would recommend using as much as 10% sugar when aiming for an OG around 1.090 or more, not only to help with efficiency but also to help dry out your beer and get better attenuation, unless your looking for something on the syrupy side.

 

Temp seems low @147 and then you added oatmeal which probably lowered the temp even more and that is assuming your thermometer is even accurate and not just slow.

 

I thought it was a little low, but then at 147 I thought it was supposed to convert more sugars, not less. I plan to check the calibration on that thermometer soon.

 

147 makes a more "fermentable" wort , but its slow at that low of a temp and it almost excludes the alpha amyalase. A mash temp of 153* would convert more sugars.

If your thermometer is slow then how would you know you've stirred enough to eliminate even colder spots?

 

I checked at a dozen spots in the mash. It came up and stayed right at 147. I need to get another digital one. My last one finally bit the dust.

 

So this is the first time checking mash efficiency or do you check it regularly and this one time it's low?

 

This is the first time to dig into it and try to maximize everything. The OG and amount of grain never seemed to add up to me. Seemed like I was using more grain than I should have to for the beer I was making. All good beers, just had to tweak recipes to get the OG where it was supposed to be. I can post some number from previous recipes so you can see how they stack up.

 

Ok. Here's a little data on my last three brews.

Island hopper IPA
26 pale malt
1 carapils
8.4 gal @ 164 mash
7.7 @ 170 sparge
1.060 into fermenter

Newcastle
30 UK 2 row
2.5 crystal 60
1 chocolate
10.5 @ 166 mash
6.5 @ 170 sparge
1.076 into fermenter

SNPA
22 US 2 row
1.5 caramel 10
1.5 carapils
7.8 @ 166 mash
8.1 @ 170 sparge
First runnings 1.0968
Last runnings 1.016
Before boil 1.030
After boil into fermenter 1.052

All 10 gallon batches. Sorry I don't have as much info on some of them.

 

The first suspects are gonna be your crush (is your new corona mill adjustable?) and your mash tun( does this drain all the way to the bottom?).

 

Are you correcting for temperature when you take your gravity readings?

Can you describe your sparging process?

 

Was that 9.5 gallons all of the liquid left after your boil or did you leave some in the kettle? If you left some in the kettle that explains some of your apparent low efficiency, if compared to numbers you see others reporting on here.

 

The grain was milled by Midwest the first time. I ran it through the corona just to make sure it was milled good enough. It was super fine with only half husk pieces remaining intact. Yes the mill is adjustable. The mash tun is a rectangular 50+ quart marine cooler with a three row rectangular copper manifold with slits cut in it. It will drain all but the last half gallon, so I usually over sparge a bit to get all I can.

 

All gravity readings are adjusted. The most recent one should be 1.069 instead of 1.068 as it was taken at roughly 70 degrees. I fly sparge in my mash tun and keep a constant level above the grain bed. Usually 1-2 inches depending on how much grain is in it.

 

My keggle leaves about 1-1.5 inches in the bottom. Usually nothing but hop residue and hot break.

 

Missing your mash target is why Rice Syrup solids and Clear candi sugar were invented

 

I may have to invest in some of those. That's what my brown sugar was supposed to be for, but I was still low with it.

 

Ever try tipping it towards the spigot while its draining? I know 0.5 gallons wouldn't cause %55 efficiency on it's own though.

What about channeling?

 

Tipping it would actually cause it to break the syphon of the manifold. I did something different with this batch than I usually do. I actually adhered to my sparge numbers. I usually just maintain a solid level in the mash til I get the volume I'm looking for, or it drops to 1.012 or so. This time I just drained the whole thing with the sparge water I was actually supposed to use. I thought that would help things, but it doesn't seem to make a difference either way.

 

With a solid inch of water above the grain I figured channeling would be eliminated.

 

I'm thinking about brewing BierMuncher's Centennial Blonde so I can compare to a tried and true recipe and see how I compare.

 

You wouldn't tip until the water went below the top of the grain bed towards the end of sparging. By then it wouldn't matter too much about the siphon.

Channeling could happen with water above the grain bed. Do you just throw a hose in the top or do you distribute the water across the top of the entire cooler? How fast are you draining?

 

Unless I was using more than the required amount of sparge water I would end up doubling the amount left in the mash tun. I set my mash tun up to pull from the center instead of one side. It's a rectangular cooler. The manifold in the bottom is 1/2 copper pipe.
--------------------------
I I
------------+------------ <=>
I I
--------------------------
Kinda like that. In the middle of the manifold is a tee that connects to a 90 that connects to a piece of pipe that connects to the valve <=>. That whole assembly is soldered together. The outer rectangle is made into two L shapes that are soldered together. I put the two L shapes in there and connect to the center stationary manifold section. I designed it to minimize channeling on the side where the valve is because I read about people having problems with that. If I tilt the mash tun, as soon as air hits the far end of the manifold, away from the valve, it won't drain past the 90 that is above the manifold that leads to the valve.

I have a rectangular manifold made to the top of the cooler. It feeds from both sides and covers the grain bed fairly evenly as long as the flow isn't too low. It has small holes drilled in it at various angles to rain down.

It takes 50-60 minutes to complete the sparge.

 

It doesn't sound like channeling.

Leaving 1.5 inches in a keggle is gonna count against efficiency even though it useless hop gunk and break material. You might try measuring mash efficiency instead of brewhouse just to get a better idea of your losses.

What are you measuring OG with? Has it been calibrated?

How about stirring? Does the manifold let clumps form on the bottom?

Any idea what your mash PH is?

 

No idea on the ph. I usually have a couple gallons of strike water in the mash tun before I start adding grain so I avoid any clumps. I use a hydrometer and a refractometer. Refractometer reads 0 with distiller water. It was used for all numbers, then the hydrometer was used to verify the final number after the wort was cooled. It reads .997 in tap water. The refractometer gave a reading of 1.074 for the OG. The hydrometer was 1.069 after temp correction. I originally meant to measure mash efficiency, but didn't get all the numbers for that on this batch. I did better data gathering on a few even earlier batches. I'll look them up and see if I have the data required to figure mash efficiency.

 

Definitely do this. Measure the pre-boil gravity and volume and use those numbers for your mash efficiency. Anything left in the keggle post-boil should not impact your mash efficiency.

Your sparging process and equipment sound good.

Honestly, I'm kind of scratching my head. I've gotten 80% on kits from midwest and that's without milling them twice. You should have no problem getting good numbers.

I like the idea of brewing a nice light grain bill and seeing what your efficiency is. The bill for Centennial Blonde is perfect. Last time I brewed it I got 87%.

 

See this

http://www.homebrewtalk.com/wiki/index.php/Batch_Sparging_Analysis

 

You implying I should batch sparge? I went with fly sparging originally because it was supposed to be more efficient. Apparently that's not so in my case. I did check some of my older batches, and it appears that 60% is where I have been running on brew house efficiency. One had 75% mash efficiency.

 

Hey, sorry I was in a rush earlier. No I wasn’t suggesting you switch to batch sparging. All in all fly sparging should be more efficient. I wanted to show the reference because it has a good graphic for showing that efficiency goes down as the OG goes up. OK now that I have more time and a beer here we go. I am going to make some assumptions just to illustrate my point. I am going to use batch sparging, but the same holds true for fly sparging. It’s just more complicated to explain.

First assume grains will yield 1.035 (35 gravity points/gallon). 1 hr boil and 5.5 gal pre-boil volume with no loss to in mash tun or in bk. Single batch sparge.

10# grain = 350 total gravity points possible. It will require 6.92 gal total to get to pre boil volume. It will give you a pre-boil SG of 1.063 @ 100% efficiency. Grain absorption 1.2 gal
20# grain = 700 total gravity points possible and will require 8.12 gal total to get to pre boil volume. It will give you a pre-boil SG of 1.127 @ 100% efficiency. Grain absorption 2.4 gal

Starting with a grist/water ratio of 1.25qt/# grain the concentration of dissolved sugar should not change significantly regardless of grist size - 10# grain in 12.5 qt and 20# grain in 25 qt should give the exact same gravity for your first runnings.

Let’s assume your first runnings measure 1.100 or 100 gravity points/gal

10# based on the water in and out 3.125 gal in – 1.925 out. 1.925gal*100GP/gal = 192.5 gravity points out of 350. 55% of the total gravity
20# based on the water in and out 6.25 gal in 3.85 out. 3.85gal*100GP/gal = 385 gravity points out of 700. Also 55% of the total gravity, which is expected.

Sparge water
10# -3.8 gal
20# - 1.87 gal

Here is where most of your loss comes from. There is an equilibrium between the sugar deposited on the grain and the sugar dissolved in the water. The sugar will move from high concentration to low concentration until an equilibrium is achieved. Thus the more water you add (low sugar concentration) the more sugar you will extract from the grain (high sugar concentration).

10# you need to extract 157.5 gravity points in 3.8 gal or 41GP/gal for 100% yield
20# you need to extract 315 gravity points in 1.87 gal or 168GP/gal for 100% yield. (This is higher than first runnings)

The problem for high gravity beers is that you can’t add enough sparge water to get an adequate sugar concentration gradient and you leave a ton of sugar behind. In order to get all the sugar extracted you would need to sparge with a lot more water. In the case presented above for 20# you would need 7.7 gal sparge water to have the same batch sparge concentration as 10# grain.
The same holds true for fly sparging, but explaining the concentration gradient is more difficult.

Hopefully this makes sense. Now I need another beer

 

Ok. So we get into a 2+2=3.5 kind of situation with the sugars. That's what I was getting from the thread so far. So, you either expect the losses and use more grain, or use more sparge water and boil it for half a day. I guess the difficulty in explaining the fly sparge comes from the fact that you have a constantly decreasing amount of sugar in the water? It's always absorbing more sugar, but less and less as it goes.

 

With all that said, for a porter like I did, is that about what I should expect? I assume I'll learn more when I do my lighter beer, and keep more detailed notes all the time. Then i can confirm whether something major is a miss, or if thats just what my system will do. I used to keep better notes; just slacked off a little I suppose.

 

You got it.

For me. I usually have about 80%+ mash efficiency with 70-75% brew house efficiency with normal gravity beers (<1.060). When I do my double IPA my efficiency drops down to 60-70% mash and 55-65% brew house.

If you haven't already search party-gyle. That's where you use the first running a for your big beer, then sparse with 5 gal and use that for a lighter session beer.

 

I just think you are using too large of a grain bill and when you use that much grain efficiency goes way down. Try a batch with 18-20 lbs of grain and I bet you will see your efficiency go way up.

 

I like the two batches off of one mash idea.

 

I haven't had the time to do a party-gyle yet, but I want to. What's cool is you collect your first runnings for say an IPA or some other pale beer. Then throw in 2-3# of dark specialty grains and do a second mash while you boil your first batch. That way you get a double IPA and porter out of the same batch.

 

Cool