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Trouble with Mash Efficiency

Hi all -

I am relatively new to brewing with only five AG batches under my belt.

I took a crack at a pumpkin brown ale today and I was really disappointed to find out that I only got the mash to convert at ~60%. Regarding the details, I mashed at 149F for 60 minutes and 2.2 qts/lb (not the plan, but after initial infusion at 164F, I had to add more water just to reach 149; adding more hot water would have exceeded the capacity of my tun). I performed a continuous sparge at 165F, collecting about 4.5 gallons of wort (3 gallon batch).

As I am trying to figure out what I did wrong, I remember that the only other time I have had such a poor conversion was also attempting a mash at 149F (that time according to plan).

Do I have to take another step when mashing at the lower ranges to make sure that conversion is in the 75% range? I imagine PH might come up; I do not currently have a good way to measure or correct for PH.

Obviously, this batch is not going to be what I intended, but I am trying to make sure that I can have better control of my mashing in future brews.

Thanks for your suggestions.

The first thing to check is instrument calibration. If your thermometer is reading 5°F high, then you could really have been mashing at 144°F, which is low enough to cause some problems. Given that it’s happened before, that seems likely.

Regarding conversion efficiency, even 75% is pretty bad. I’d say that anything under 90% indicates a problem. Checking pH is definitely a good start. Get some ColorpHast strips - 100 of them cost $20, and you can cut them in half if you’re cheap like me.

No offense, but could you post your measurements so someone else can double-check your calculations? It’s certainly possible you just fat-fingered something.

No offense taken, I am certainly willing to give as much information as possible to help figure this out.

Mashed 8 lbs grain (2-row, 20L, 120L, chocolate, and flaked barley) with 1lb roasted pumpkin.
Strike water was at 164F. I preheated the MT (maybe not enough), but once added the grain and pumpkin, only measured ~145F. To get up to 149F, I added water up to 19.5 qts, 6 qts higher than my target mash ratio.
Started my sparge with 170F water and after recirculating the first quart, continuously sparged until I collected 4.5 gallons.
Didn’t take a pre-boil hydrometer reading.

Calculated OG: ~1.071
Actual OG: 1.053

Regarding PH control, I can do a little more reading about measuring and controlling it, but have previously followed the premise that if my process was consistent, PH would basically take care of itself.

My best ever conversion has been 82%; any thoughts on possible causes for this? I guess maybe the better question is why would my PH be so out of whack?

Thanks again.

I brewed my first AG batch on Friday just happened to be a pumpkin ale. My efficiency turned out to 50%. After doing some investigating my thermometer that I used during the mash was reading about 10 degrees off. I am almost 100% sure that was why my efficiency sucked so bad. It was a learning experience and I am only sure my future AG batches will only continue to get better.

To eliminate one more item, I checked my thermometer the only way I could think of, measuring the temperature of boiling water; the result is 211F, so not far off. I guess the hydrometer could also be off, but not sure what the probability of this is.

There is definitely a possibility of hydro-meter’ calibration as most of the hydro meter are calibrated so that they give the most accurate reading at the 59 to 60 degree Fahrenheit. If you are having doubt regarding your hydro-meter or thermometer then it would be better to re-calibrate them.

I think you’re talking about your overall mash efficiency (as opposed to conversion efficiency), so the first thing you should do is figure out what your conversion efficiency is. That will tell you where the problem lies. ... Efficiency

You’re absolutely right. After reading just the first part of the braukaiser efficiency article, I understand that I am talking about total mash efficiency, not conversion. Since I did not take pre-boil measurements this time, I will have to wait until next time to try to nail down where my issue is.

On a positive note, I eliminated another possible issue tonight in checking the calibration on my hydrometer; it’s right on, so the problem isn’t in instrumentation.

Regarding PH, I still have some Palmer reading to do about adjusting PH, but what is the general process for getting a PH reading in the MT and adjusting PH, if necessary?


One more note after a bunch of reading tonight: the color came out much lighter than I expected. Does this further the possibility of a PH problem?

Pull a small sample of wort, let it cool to room temperature in a sealed container, then dip the strip in the wort for a few seconds, shake off the excess, and take the reading.

Adjusting mash pH is going to depend on how far off it is, and in which direction. I’d start here:

, but I may be biased. :wink:

As an aside, even though you dont have a PH meter or etc… to check the mash. If you have access to your water values and can download a free app called bru n water you can with a great deal of certainty do some salt, acid additions within the app to give you an idea where your PH might be with/ without adjustment I have nothing to do with the app. But I have used it exclusively since it was created a year ago and every time I check to see where my PH’s are it is in line with what the spreadsheet said it should be with my “virtual” premash adjustments.

There are many threads I and others have spoken about this software and myself I think it plain rocks.
And it makes mashing PH and other water subjects a veritable breeze for newer brewers.

Here is a reply I just posted today about this very subject:


Here is Martin B’s website for the free app “bru n water”

even if the therm is right at 32 and 212 it could be off at 150, check it there also.

Thank you for all the helpful suggestions.

I’ve checked out a couple of the PH spreadsheets (Palmer and Braukaiser) and will be using them going forward for pre-brew water corrections.

While I’m sure that the PH didn’t help and wouldn’t have helped the finished beer, as I review some notes, I am more confident that the real problem was mash time, temperature, and adjustments. I targeted 153F, missed it, hitting only 149F. I really should have stopped right there, made some room in the MT and added more hot water. If not that, I should have mashed for at least 75 mins. Instead, I left the missed temp and only mashed for 60 mins…serious rookie move :slight_smile:

I tasted this week (after 1 week in the primary) and it’s pretty much awful; dry, alcoholic, and generally lacking any malt character.

I think I am going to chalk this one up to a great learning experience and just dump it.

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