Starch Conversion but Still Low Mash Efficiency?

I have a couple AG batches under my belt and have been doing tons of research. I have been getting very low efficiencies (50-55%). I recently got my Ward water test and used Bru'n Water to get the right chemicals for my brew (My water had been WAY too alkaline). I was hoping today would be the day it all came together.

I did an iodine test for the first time and I think it showed conversion. I didn't really see any difference in the color of the iodine. If anything it got lighter when mixed with the wort. It definitely didn't turn purple or black. I used my new refractometer for the first time on the first runnings out of the tun and only got 1.065. The table that everyone here references shows that I should have been at a 1.090 for my 1.33 grist ratio. It seems to me that my mash efficiency was only 72% (65/90). Is that right? What should one expect from a mash efficiency? Is this telling me that my crush just isn't good (getting it crushed by the LHBS) or am I not understanding something?

On a further note, according to the Brewer's Friend efficiency calculator, I ended up at only 50% efficiency for what went into the fermenter. Do I suck at sparging too? FYI, I batch sparge and stir the crap out of it before draining.

Noob question but could you please provide a link to the table?

You can definitely pass the iodine test and get nowhere near full conversion. I recently tested my conversion efficiency using the LHBS crush. At 30 minutes, I had only 83% conversion but no "black". After 60 minutes, I was at 91%. At 90 minutes, I was up to 98%. Iodine is just testing for starch in solution. If it is still locked up inside the grain, iodine won't test for it.


The most likely reason you are getting such low conversion is your crush. If you are getting 50-55% total and only 72% conversion, you are only losing 17-22% in your sparging and dead space. If you were getting 100% conversion, that would equate to upper 70's-low 80's.

Eric191312,
Here is one link:
http://cdn.homebrewtalk.com/images/9/6/3/0/8/first_wort_gravity-57692.gif

I know there is an entire article that goes with it but I can't remember where I found it.

Bill,

I appreciate your answer. Very informative. Am I calculating the efficiency correctly? 65/90 = 72% Do you think a 90 minute mash would do anything for me or do I need to go ahead and get a mill? Is it reasonable to expect 100% from your mash efficiency?

dachbach said:

Eric191312,
Here is one link:
http://cdn.homebrewtalk.com/images/9/6/3/0/8/first_wort_gravity-57692.gif

I know there is an entire article that goes with it but I can't remember where I found it.

Bill,

I appreciate your answer. Very informative. Am I calculating the efficiency correctly? 65/90 = 72% Do you think a 90 minute mash would do anything for me or do I need to go ahead and get a mill? Is it reasonable to expect 100% from your mash efficiency?

Click to expand...

Here it is...footer on the chart was the clue

http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency

What was your grain bill, mash water quantity, and sparge water quantity?

Yes, you should be able to get pretty darn close to 100% conversion. A finer crush is obviously the simplest way to make sure you do.

If that isn't in the picture right now, you can mash longer, stir more etc. Both of those will help. I'm usually around 75% total efficiency with a 60 minutes mash, but that jumped to 82% in the experiment I did. (Conversion went up 7%, and the total followed) You might want to try it and see how big of a bump you get. Ultimately though, I think addressing the crush is a better long term solution.

The formula above is the approximation. If you follow that braukaiser article, he's got the complete calculations. The chart is also an approximation that assume your grain bill is at 80% fine grind. If you had a lot of specialty grains, your max might be lower. Really though, the approximations are close enough to tell you if you are getting good conversion, and at this point, you aren't.

Okay, so I brewed again today and had the exact same thing happen. I got 1.065 for my first runnings and had 1.050 pre-boil for 4.6 gallons. This tells me I got 72% conversion/efficiency from just the mash and 57% efficiency after including sparge. I ended up post boil with 1.056 and 3.75 gallons (52% efficiency).

I've talked to two employees at the LHBS who mill their grains at the LHBS when they brew. One gets a total efficiency of 65% and the other one 77% so they're obviously not having the same conversion problems I'm having.

Could there be something wrong with my mash tun setup that's causing this conversion/efficiency problem? I'm using a cylindrical 5 gallon cooler with stainless steel braid. I'm hitting my temps and I only drop about a degree during the mash. I use two thermometers and they've both been calibrated.

I would be perfectly happy with 65-75% total efficiency but something from my mashing seems to be preventing that.

There is obvious some sort of issue w/your process, you should get conversion efficiency above 90%.
If you already didn't be sure to read this:
http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency
http://braukaiser.com/wiki/index.php?title=Troubleshooting_Brewhouse_Efficiency

I never struggled with conversion but I found jump in efficiency into the kettle after tightening mill gap, adjusting pH and stirring mash 30 minutes after dough in.
Good luck!

dachbach said:

Okay, so I brewed again today and had the exact same thing happen. I got 1.065 for my first runnings and had 1.050 pre-boil for 4.6 gallons. This tells me I got 72% conversion/efficiency from just the mash and 57% efficiency after including sparge. I ended up post boil with 1.056 and 3.75 gallons (52% efficiency).

I've talked to two employees at the LHBS who mill their grains at the LHBS when they brew. One gets a total efficiency of 65% and the other one 77% so they're obviously not having the same conversion problems I'm having.

Could there be something wrong with my mash tun setup that's causing this conversion/efficiency problem? I'm using a cylindrical 5 gallon cooler with stainless steel braid. I'm hitting my temps and I only drop about a degree during the mash. I use two thermometers and they've both been calibrated.

I would be perfectly happy with 65-75% total efficiency but something from my mashing seems to be preventing that.

Click to expand...

Hi dachbach,
I think this will help
As I read this thread, I'm thinking he has a "braid". Switch up to a manifold setup and you will see a significant improvement in your mash efficency.

Anyway, The best setup according to John Palmers book How to brew" http://www.howtobrew.com/appendices/appendixD-1.html
The quadrant circlular design will allow for the best mash efficiency.
My brother made me one of copper and brass. I never get stuck sparges and end up around 82+%.

I think I might go to a manifold soon, even if it's just to have a more sturdy setup compared to the braid that's getting damaged when I stir.

I understand that a manifold should help with my lautering efficiency. However I think my issue right now is strictly mash efficiency. In addition to the first runnings gravity sample I took, I also got a sample of the wort from inside the mash tun before I lautered. I just took the top off my tun and got a sample for my refractometer.

So my lautering setup (braid vs. manifold) shouldn't effect my reading of initial mash conversion, right? Both the pre-lauter reading straight from the tun and my reading of first runnings in the brew pot before sparging were 1.065. They should have been 1.090 with my 1.33 grist ratio.

Does this make sense? Am I just not understanding something? Is there something simple I'm missing? I'm running out of ideas...

There are better teachers here than I.
This is how I understand the principle.
Malted grain has an expected amount of fermentable sugar that can be rinsed from it after the mash is complete.
"Effeciency" is the percentage of fermentable sugars rinsed from the grain after the mash is completed. Therefore a higher effeciency is nothing more than a more successful sparge.
The manifold is more "effecient" since the surface area is larger as long as it is not so large as to allow the sparge to travel direct to the manifold along the wall sides of the tun during the sparge.
Hence the circular quardrant diagram showing coverage of the floor without being to colse to the sidewall is best design for maximum effeciency.

Anyone care to 2nd?

You did correct the sg reading for temperature right? Do refracometers automatically do that? Never used one.

This isn't any issue related to sparge efficiency. I know this because OP measured the gravity in the mash. I batch sparge with a bazooka coil in a rectangular tun and get 75 to 80% efficiency all the time. OP needs to fix what is happening in thesaurus, and then work on optimizing sparge technique.

""Effeciency" is the percentage of fermentable sugars rinsed from the grain after the mash is completed. "

There are lots of measures of efficiency, and this is one. You can measure Mash efficiency, efficiency to the kettle, efficiency to the fermentor, efficiency to the keg etc. All are measures of how much of the original sugar is still in use at various stages of the process.

The issue here is mash efficiency.

So, I still think the crush is the most likely culprit. If you can't adjust that, then you'll have to concentrate on optimizing the other aspects of the mash.

1) stir the heck out of it, then stir some more.
2) Get a water report or start using RO water - and adjust either using some brewing water software.
3) Double check thermometers etc to make sure you hitting your temps.
4) Try mashing a little longer to make up for some of the less than ideal parameters.

If you are feeling adventurous, you could also give decoction mashing a shot. Boiling the grains/thick mash does a heck of a job breaking them down and getting the starch out.

As for the "switch from a braid to a manifold", I use a bazooka screen and my efficiencies are fine (upper 70's on a bad day, to 80's most of the time). I have my LHBS grind my grain, but have them run it through the mill twice. The only thing I do with my water (city water) is filter and adjust pH.

I've noticed that my efficiency is higher when there are darker grains in the mash than when mashing only pale malt--don't know why this would be, unless my pH is just not quite dialed in without the darker to acidify. I also notice that I get higher efficiency with Maris Otter than with US 2 row.

You mention first runnings so I assume you are batch sparging like me. If that's the case then you don't need a manifold unless you plan to fly sparge (or you just like to tinker with stuff). I've been using the same ss hose braid for about 5 years now and I consistently get full conversion (usually mash for an hour - somethimes longer) and I always get between 75 and 80 percent brewhouse efficiency - and that's with Austin Homebrew Supply's crush. Some time a few years ago I brewed a couple of batches and seemed to have the exact same problem you describe. I hadn't changed anything in my process, so I checked all my equipment. It turned out my thermometer was off. After I re-calibrated it everything was fine. Have you checked yours to make sure it's calibrated correctly? Just a thought.

By the way, the higher the gravity of your beers, the lower the efficiency you can expect.

Thanks for all the replies. I appreciate you guys trying to help me out.

eric19312, what do you mean by happening in thesaurus?

OP needs to fix what is happening in thesaurus

Click to expand...

Billl, my first thought was the crush too but after talking to a couple different employees that use the same LHBS crush and get good efficiency, I wasn't so sure any more(unless those two guys just don't know what they're talking about). I've had them double crush my grains the last two times as well.

The issue here is mash efficiency.

So, I still think the crush is the most likely culprit. If you can't adjust that, then you'll have to concentrate on optimizing the other aspects of the mash.

1) stir the heck out of it, then stir some more.
2) Get a water report or start using RO water - and adjust either using some brewing water software.
3) Double check thermometers etc to make sure you hitting your temps.
4) Try mashing a little longer to make up for some of the less than ideal parameters.

Click to expand...

1. I stir a lot but can always stir some more.
2. I got a water report and adjust using bru'n water
3. I have a digitial thermometer that reads the same as my normal thermometer. It read right at 212 the other day while boiling. I will check it in a cup of ice water to make sure it reads 32.
4. I have not tried this yet.

I could be wrong, but I'm under the impression that suggestions like these would help a little bit in efficiency, but not be enough to explain the huge difference I'm seeing (only 70% mash conversion). Is that an accurate statement?

I guess I'm at the point where I have to find another LHBS or buy my own grain mill. This is driving me crazy.

Dang autocorrect


I meant "in the mash" as opposed to "in the sparging"

Are you adjusting pH based on Bru'n water? I found it's recommendations somewhat extreme compared to some other calculators.

Can you post a picture of your typical crush? I believe a good crush is important and do have my own mill, but I think much of the benefit relates to balancing what is best for mash (darn close to flour is how they measure potential extract) vs what is best for sparging (intact hulls). Given the issue are describing you need a finer crush. Until you can get your own mill try having the local store double crush.

"I could be wrong, but I'm under the impression that suggestions like these would help a little bit in efficiency, but not be enough to explain the huge difference I'm seeing (only 70% mash conversion). Is that an accurate statement?"

Well, there really aren't THAT many things you can adjust. We're talking about putting hot water on grains and waiting a bit. You either tweak the grains, the water, how you combine those 2, or how long you wait. The combination of those things will make you range from 0 to 100%.

If you've done the same water adjustments to each batch, that is another likely issue. You might try just a 50/50 mix of tap water and bottled water with no additions. That probably won't match the "ideal" version in the calculators, but it is a pretty reasonable starting point for most municipal water. Are you testing PH to make sure you aren't too far out of the ballpark with your current water?

eric19312 and billl, both of you guys mentioned adjusting/testing ph. My water is extremely hard and extremely alkaline. I mix 50/50 with my water and distilled and also add phosphoric acid and gypsum to get to whatever profile my beer calls for. Bru'n water tells me what my adjusted ph should be based on my additions but I have never actually tested the ph myself. I've just assumed bru'n water is right. Sounds like my next step will be to purchase some ph testing strips to confirm or deny.

I will post a picture of my crush next time I brew.

On a side note, my inefficient beers still taste good! I shared a recent Amarillo/Chinook Pale with family and friends this weekend and it was a big hit.

I use Bru'nWater and get good result from it, but yes you do need to know the ph of your water. A swimming pool test kit will get you close and make sure you don't have a big issue. If you don't input a valid ph, you could be putting in too much acid.

I have tested the ph in the mash on a few occasions. Everytime, the ph was as predicted by Bru'nWater.

Let me clarify. The ph was tested when I got my water report back from the lab. I use that number as the basis for my additions. I have never personally checked it with ph strips after additions to see if it matches bru n water.

Without running out for a pH meter, you can get relatively accurate results using the colorpHast 4-7 range pH test strips for about $20 lifetime supply (cut them in half long ways to double the quantity).

You can have starch negative tests in the wort but still have plenty of starch in large particulates of endosperm. This can happen even more easily in protein heavy malts and unmalted adjuncts that have not been protein rested or that have not been at gelatenization temps. Anything particularly interesting about your grain bills?

If not, take a 60 minute starch test and gravity reading, then grab a cupfull of thick mash and "physically mash" it up with something. Starch test again.

I just wanted to give an update that I went to a different HBS this time for my grains and got nearly 100% mash conversion with a total brewhouse efficiency right at 70%! I was getting around 50%. So I guess it was just in the milling of the grains. These grains had WAY more powder in them. It looked like a total different product than what I had been used to. I even had a brief stuck sparge.

However, my grain bill was 27% wheat. Wheat doesn't have a husk and is only powder, correct? Would that be the entire explanation for the seemingly finer crush? Does the wheat explain my conversion and efficiency increase or can I attribute that to a better overall crush? I'm really hoping I've figured out my problem...