My first AG homebrew -- English Bitter

Okay, I did my first all-grain homebrew this past weekend. It's an English Bitter. The recipe called for 6.75 lb of Maris Otter 2-Row and 0.5 lb of Crystal 60L. So, that's a total of 7.25 lb of grains. I figured my efficiency would be low on my first AG, so I added another lb of Maris Otter. I was correct. My efficiency was low about 62%. But, my main problem was keeping a constant temperature in my mash/lauter tun. I used a 48 qt Igloo cooler with a Bazooka braid for batch sparging.

I added 2.6 gal of 178F water to the cooler. Waited until the water cooled to 162F and added the grains. Temperature stabilized at 150F. It was right on according the recipe. I waited 1/2 hour to stir and take another temperature reading and it dropped to 144F. I lost 6F in 1/2 hour. I know the cooler is pretty empty with this lighter style of beer, but I expected the temp to hold better than that. I had to keep adding hot water to keep the temp up above 150F.

So, what can I do get the temp constant in the cooler? Next time, I'm tempted to do the mashing in my 10 gal pot on the burner to keep the temp under control.

Also, why is my efficiency so low? Is it because of my temp issues? Or, is it my sparging technique? Maybe the grains weren't ground fine enough (I got them from Austin Homebrew preground)?

TIA.

Seems like 150 is a bit low to begin with. Most mashes want 154 for a single infusion. That is a lot of heat to be losing in an hour. Did you pre-heat your MLT? That makes a big difference. Pour 1-2 gallons of hot water and let it sit while you get the mash-in water to the right temp. Then whatever temp you lose to ambient, will not happen. The cooler should work fine for you, most people lose less than a degree in an hour. Once it is figured out, I am sure you will be fine.

I second Kayos. Put a couple gallons of very hot water (near boiling) in there to preheat the cooler. Toss it, then add your strike water, stir and let set for 40-45 minutes. I bet it will only loose a couple of degrees in that time.

I agree with the others that you need to pre-heat the tun, but you should use enough hot water to fill it up to the level that your mash will reach.
As for efficiency, it could be the crush, or the pH, or the mash temperature, or the equipment, or the way you sparged, or it could even be an inaccurate hydrometer, not applying temperature correction, or reading the hydrometer wrongly.
To find out where the problem is, you need to take the gravity of the first runnings, and the last runnings, as well as the pre-boil gravity and volume.
Also, when taking the pre-boil gravity, make sure the wort is stirred really well before taking the sample.

With some more information, we can probably figure out where the cause of the problem is.

-a.

Kayos said:

Seems like 150 is a bit low to begin with. Most mashes want 154 for a single infusion. That is a lot of heat to be losing in an hour. Did you pre-heat your MLT? That makes a big difference. Pour 1-2 gallons of hot water and let it sit while you get the mash-in water to the right temp. Then whatever temp you lose to ambient, will not happen. The cooler should work fine for you, most people lose less than a degree in an hour. Once it is figured out, I am sure you will be fine.

Click to expand...

The recipe called for 150F. I originally planned on 153F but the temp dropped too fast.

I didn't pre-heat the MLT? I figured I wouldn't need to if I just went higher than I needed. But, I guess that didn't work out.

ajf said:

I agree with the others that you need to pre-heat the tun, but you should use enough hot water to fill it up to the level that your mash will reach.
As for efficiency, it could be the crush, or the pH, or the mash temperature, or the equipment, or the way you sparged, or it could even be an inaccurate hydrometer, not applying temperature correction, or reading the hydrometer wrongly.
To find out where the problem is, you need to take the gravity of the first runnings, and the last runnings, as well as the pre-boil gravity and volume.
Also, when taking the pre-boil gravity, make sure the wort is stirred really well before taking the sample.

With some more information, we can probably figure out where the cause of the problem is.

-a.

Click to expand...

For the first runoff, I got 2.9 gal at 1.040 and for the second runoff I got 3.4 gal at ? gravity.

Final pre-boil gravity was 1.028 with 6.3 gal total. Post-boil was a 5 gal at 1.035. The recipe called for 1.036, so I missed it by a point but I used an extra lb of grains, remember?

I'm not familiar with the igloo, by my rubbermaid will hold at 155 for easily, 45 minutes before loosing a single degree.

Preheating is not the issue. Preheating simlpy reduces the initial temp-reduction shock that occurs when you add the strike water.

Once added, the cooler walls immediately come to temp. Temp reduction shock can be compensated by increasing the strike temp. Now the critical question is how long can the cooler hold the temp.

For $39.00 a rubbermaid may be the ticket.

I agree with BierMuncher. I have a 10 gal Rubbermaid M/L tun that only loses at most, 2f in a 90min. mash.

BierMuncher said:

I'm not familiar with the igloo, by my rubbermaid will hold at 155 for easily, 45 minutes before loosing a single degree.

Preheating is not the issue. Preheating simlpy reduces the initial temp-reduction shock that occurs when you add the strike water.

Once added, the cooler walls immediately come to temp. Temp reduction shock can be compensated by increasing the strike temp. Now the critical question is how long can the cooler hold the temp.

For $39.00 a rubbermaid may be the ticket.

Click to expand...

OldFarmer said:

I agree with BierMuncher. I have a 10 gal Rubbermaid M/L tun that only loses at most, 2f in a 90min. mash.

Click to expand...

Yep, mine too.

BierMuncher said:

I'm not familiar with the igloo, by my rubbermaid will hold at 155 for easily, 45 minutes before loosing a single degree.

Preheating is not the issue. Preheating simlpy reduces the initial temp-reduction shock that occurs when you add the strike water.

Once added, the cooler walls immediately come to temp. Temp reduction shock can be compensated by increasing the strike temp. Now the critical question is how long can the cooler hold the temp.

For $39.00 a rubbermaid may be the ticket.

Click to expand...

I was wrong. It actually is a Rubbermaid. I bought it at Walmart for less than $15. Maybe the walls and lids are too thin????

Wrap the sucker up in a blanket or some towels. It seems that the lid looses the most heat. Test it with some hot water to see if holding temp improves.

this might be a dumb question, but are you closing the lid?

It sounds to me like you did a fine job of preheating the cooler by using water above your strike temp. This is what I do and it works very well. I think the only thing you did wrong was to keep opening the cooler. With that small amount of grain and that much empty air space every time you opened the top of the cooler a bunch of your heat went up and out, and was replaced by cooler air.

Next time dump in your strike water just like you did (a few degrees high) to preheat the tun and close the lid. It won't take long for the cooler to absorb all the heat it needs to equalize with the water. When the water is at the proper temp dump in your grains and stir it well to make sure there are no dough balls, then just walk away. Don't even think about opening the cooler until it's time to add your mash out infusion or start your sparge.

As already stated preheating or not makes little difference as long as you compensate your strike water temperature with the caveat that the parts of the cooler not in immediate contact with your mash will absorb some heat over time. This would include the upper walls and the lid. Insulating will help. I think your biggest issue is your thermal mass. You are mashing a relatively small amount of grain in a big cooler. I have two tuns for this very reason and use the smaller 4gal one for low gravity beers like bitters, scottish 60/s and milds. Even with insulation it drops about 2-3F over 60 minutes, my 12g cooler with bigger beers only drops about 1F.

devils4ever said:

I was wrong. It actually is a Rubbermaid. I bought it at Walmart for less than $15. Maybe the walls and lids are too thin????

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$15.00 for a 12 gallon cooler?

Does it look like this?

To get back to the original efficiency question, the first thing to do is to determine where the efficiency losses are occurring.
You say your first runnings had a gravity of 1.040. This seems very low for the first runnings off 8+ lbs grain. It could either be a mash problem, or a sparge problem.
At what temperature did you take the gravity reading, and did you apply any temperature correction? If you measured hot, and didn't correct for temperature, then the true gravity could have been considerably higher. Assuming that temperature compensation was made, then you either had a poor mash, or you didn't sparge correctly.
Did you check the temperature of the mash after adding the sparge water? Ideally, this should be about 165 - 170 degrees. If less, then your sparge will not be as efficient as it could be.
Did you give a good stir after adding the sparge water? This is essential when batch sparging.
Unfortunately, you didn't get the gravity of the second runnings. Ideally, this should be about 1.015 - 1.010 (after temperature correction). If much higher than this, your sparge technique/equipment needs to be improved as you are leaving too much sugar behind after the sparge.
As for mashing in the kettle, I did this successfully for many years. It's a little bit more work, but not much.

Hope this helps,

-a.

I have the rectangular 48 qt Rubbermaid cooler.

I didn't open the lid until 30 min was up and it was time to stir.

I'm guessing my thermal mass was small with a lot of empty space?

I cooled the sample when I took a gravity reading. I didn't measure the temp but it was close to room temp.

why did you wait for the two gallons of water to cool to 162 degrees?
I heat my strike water to 175 dump it in the lauter/tun add grains and stir gives me a mash temp around 152. I use a rectangular igloo, i think its a 28 quart cooler. I think you let the water cool down too much before adding your grains.

devils4ever said:

I have the rectangular 48 qt Rubbermaid cooler.

I didn't open the lid until 30 min was up and it was time to stir.

I'm guessing my thermal mass was small with a lot of empty space?

I cooled the sample when I took a gravity reading. I didn't measure the temp but it was close to room temp.

Click to expand...

I kind of figured you were using a thin-walled rectangular cooler when you mentioned the temp loss. The Rubbermaid that we all use (as pictured in Biermuncher's post above) has walls around 2" thick compared to the 1" or so you have with a standard picnic cooler. That is where you are losing all of your heat. You did the right thing preheating the cooler with 178 water. Either go with the Rubbermaid (somewhere in the $50 ballpark) or use blankets to insulate as recommended above.

Hey, Biermuncher - I have the same thermometer as you have pictured above.

devils4ever said:

I have the rectangular 48 qt Rubbermaid cooler.

Click to expand...

That's the problem.

A rectangular cooler like that is for keeping a chest full of ice and beer cold for a short period of time....like a picnic.

The round coolers are meant to keep ice water at ice-water temperature all day long for a highway construction crews working out in 110 degree temperatures.

Get a "water cooler" cooler and see what a difference it makes.

tgreene7 said:

why did you wait for the two gallons of water to cool to 162 degrees?
I heat my strike water to 175 dump it in the lauter/tun add grains and stir gives me a mash temp around 152. I use a rectangular igloo, i think its a 28 quart cooler. I think you let the water cool down too much before adding your grains.

Click to expand...

I added 178F water to the cooler. I waited a minute to measure the temp and it was too high. So, I waited a few more minutes and it was too low! It dropped fast before I had a chance to add the grains.

I might be tempted to mash in the brewpot. At least I can add heat if I need it. I can still use the cooler for lautering/sparging.