Impatient Mash

I am making a 2.2 gallon American Brown Ale because I wanted to test this beer out first before I made 5 gallons. Anyway, I am using a 10 gallon home depot mash tun. I heated my water to about 180 and left it in the mash tun to heat it up. I opened the lid about 10 minutes later to find it at 170ish. I then waited a few minutes for the temp to go down but this cooler is real good at holding temperature. After around 10 minutes the temp was like 168 and I got impatient so I through in all the grains hoping that would bring it down to around 155. I wanted to mash at 153. To my chagrin the temp was like 160. It didn't get to around 155 for at least another 15 minutes. I then let is mash for around an hour.

After sparging and doing a second running I collected all my wort. I added a little tap water to bring my volume to around 3.2 gallons before boiling. I took a gravity reading after doing a temperature adjustment and adjusted for wort volume. I saw that I was at 1.033. I was hoping for 1.060. That is way off! My calculations were correct with my malt bill.

76% Efficiency
3.75 2 row (80% of total grist)
.66 Brown Malt (10%)
.25 Caramel 60 (5%)
.14 Special B (2.5%)
.12 Wheat (2.5%)

My question is did the initial 15 minutes with the high temperature prevent proper sugar conversion? How could I be so low? I then decided to add some DME at around .75 pounds to build up the alcohol. After boil, I took a reading at room temp with a 2.2 gallon wort and it was like 1.072. Wow! Now it is too high. What went wrong?

I understand correctly, you took a reading pre-boil and it was 1.033? Then you boiled off a gallon of water. That would definitely make it closer to the 1.060 you were looking for. Or did I miss the boat and it was 1.033 after the boil?

When you sparge, you will end up with the highest density wort at the bottom, and much lower density wort at the top.
If you then add some top-off water to the wort, you will have even lower density wort at the top. You need to stir really well to mix it up before taking a gravity reading.
Also, the temperature corrections for hydrometers are notoriously unreliable at temperatures over about 100 degrees.
You added enough DME to raise the gravity to about 1.064 after boiling down to 2.2 gallons if the pre-boil gravity really was 1.033, but you ended up with 1.072 after boiling down to 2.2g which indicates your true pre-boil gravity was close to 1.040

-a.

tochsner said:

I understand correctly, you took a reading pre-boil and it was 1.033? Then you boiled off a gallon of water. That would definitely make it closer to the 1.060 you were looking for. Or did I miss the boat and it was 1.033 after the boil?

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I got the 1.033 after I had calculated the hydrometer temperature correction. Then I had calculated that after I boiled off 1 gallon it would be close to 1.046. Still .015 points below my target.

ajf said:

When you sparge, you will end up with the highest density wort at the bottom, and much lower density wort at the top.
If you then add some top-off water to the wort, you will have even lower density wort at the top. You need to stir really well to mix it up before taking a gravity reading.
Also, the temperature corrections for hydrometers are notoriously unreliable at temperatures over about 100 degrees.
You added enough DME to raise the gravity to about 1.064 after boiling down to 2.2 gallons if the pre-boil gravity really was 1.033, but you ended up with 1.072 after boiling down to 2.2g which indicates your true pre-boil gravity was close to 1.040

-a.

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AJF, i think you hit it right on the head. I totally took a cup and scooped up the wort from the top after I added tap water. I stirred it for like 10 seconds. Clearly that was not enough time. Plus I took the reading at like 120F, which you pointed out was a negative. I took the cup of wort and put it in the freezer to cool but it was just taking forever and I got impatient.

Just for the record though, is the higher temperature mash at around 158-160 a negative aswell. I mean that interms of it affecting how much sugar I can extract. I understand that higher temperature mashes produce more dextrin sugar that cannot be fermented by beer yeast. My question is however, is sugar still extractable at that temperature?

Next time, mash a little thick so that you can adjust the temp by adding a bit of hot or cold water as needed. You need to hit you temp.
Why did you have to add tap water to hit your pre-boil volume? It would have been better to sparge a bit more and use that to get your pre-boil volume.

acidrain said:

Next time, mash a little thick so that you can adjust the temp by adding a bit of hot or cold water as needed. You need to hit you temp.
Why did you have to add tap water to hit your pre-boil volume? It would have been better to sparge a bit more and use that to get your pre-boil volume.

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I agree, maybe I should look into a thicker initial mash and adjust accordingly with water.

The reason I added tap water is because I had initially added 1.33/qt per pound which put me at 6.5 quarts or ~1.6 gallons. My first runnings were at around 1.4 gallons. I needed to sparge with another ~1.8 gallons. After that I collected around 1.5 gallons. I was still short so I just added some water to bring up the volume. Maybe I need to reevaluate sparging techniques. Any advice?

You are correct that being at the high end of the mash range, you will create sugars that cannot be metabolized by beer yeast. However, gravity should not be affected. You extracted the "correct" amount of total sugar, regardless of fermentability.

The higher the temperature, the quicker the enzymes get denatured. However, this is not instantaneous. I takes time for the enzymes to be denatured.

As freisste said, you will have extracted all the sugars that you could, but some of those sugars may not be fermentable. I don't know how quickly Beta Amylase gets denatured, but I wouldn't worry about it. You may end up with a slightly higher FG than intended, but I doubt that it will produce a bad beer.

-a.

Thanks guys for the responses, my beer is currently in ferment mode and I plan on leaving it in there for a solid 2 weeks before I take a gravity reading. I will post the FG when I get it and keep everyone updated on how the beer turns out. Hopefully it'll be somewhere in the ballpark of my vision