First batch sparge session - Questions

I have just completed my first batch sparge brewing session using my newly-constructed cooler MLT and I have some questions.

First, let me say that I have being doing all grain brews for several years using the fly sparge method and I have that whole process dialed in to the point where I can hit predicted SG numbers right on. I decided to try batch sparging because the idea of decreasing the amount of time spent sparging appealed to me.

So, I read about batch sparging and built the MLT. When figuring out the recipe (a British bitter) I reset my expected mash efficiency from my usual 82% down to 70% according to the advice I read here and elsewhere for first time batch spargers.

To calculate my water volumes and temps I used the calculator at Brewheads.com. I was very careful when weighing the grains and measuring the water quantities.

Here are my questions:

1) I preheated the cooler with 180 water, dumped that out and added the grain and the calculated volume of water at the correct temperature (164 deg). The mash temp ended up 2 degrees higher than it should have been. Any idea why that would be? Did I heat the cooler up too much?

2) The volume of wort collected from the mash was .375 gal less than the calculator said it would be. I assume that it was because of the volume of liquid left at the bottom of the MLT between the drain and the bottom of the vessel. Yes? No?

3) When draining the wort, do you open the valve fully or do you do a slow runoff? I did a fairly slow runoff for the first draining and then a faster, almost wide open for the second. Does the rate of the runoff matter?

4) Much to my surprise, I achieved an efficiency of 82%, Is that typical or did I just get lucky?

Thanks for your help.

With my limited experience.

I preheated the cooler with 180 water, dumped that out and added the grain and the calculated volume of water at the correct temperature (164 deg). The mash temp ended up 2 degrees higher than it should have been. Any idea why that would be? Did I heat the cooler up too much?

Click to expand...

It's much easier to stir the mash to cool to the desired temperature than heat it.

The volume of wort collected from the mash was .375 gal less than the calculator said it would be. I assume that it was because of the volume of liquid left at the bottom of the MLT between the drain and the bottom of the vessel. Yes? No?

Click to expand...

Yes, dead space

When draining the wort, do you open the valve fully or do you do a slow runoff? I did a fairly slow runoff for the first draining and then a faster, almost wide open for the second. Does the rate of the runoff matter?

Click to expand...

Start slowley, allow the grain bed to compact into a "filter". Once it's flowing you can open it up. Do this on initial runoff and sparge.

4) Much to my surprise, I achieved an efficiency of 82%, Is that typical or did I just get lucky?

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I usually get upper 70's and 80's mash efficiency, it's the brewhouse efficiency that knocks me down

Another early riser in New England

MrAverage said:

Here are my questions:

1) I preheated the cooler with 180 water, dumped that out and added the grain and the calculated volume of water at the correct temperature (164 deg). The mash temp ended up 2 degrees higher than it should have been. Any idea why that would be? Did I heat the cooler up too much?

Click to expand...

Could just be a stirring issue. I often find that my temp is a little off when I first check the temp but, after stirring the mash and letting it sit to equalize for a few minutes, it seems to give a more accurate temp. I have a digital therm. with a probe that I leave in the mash with the lid closed and that way I can keep an eye on the temp without opening the lid too much. I do cover the cooler with a big blanket to help with insulation.

MrAverage said:

2) The volume of wort collected from the mash was .375 gal less than the calculator said it would be. I assume that it was because of the volume of liquid left at the bottom of the MLT between the drain and the bottom of the vessel. Yes? No?

Click to expand...

Can't help you there. I've never tried to predict what I'm going to get from my first runnings. I just measure what comes out and then subtract that from my total pre-boil volume, then I know how much water to sparge with. I usually divide the sparge amount into two equal sparges. Did that make sense?

MrAverage said:

3) When draining the wort, do you open the valve fully or do you do a slow runoff? I did a fairly slow runoff for the first draining and then a faster, almost wide open for the second. Does the rate of the runoff matter?

Click to expand...

I typically start slow and then, by the time I've finished recirculating about a gallon, the grain bed is usually pretty set so then I let er' rip.

MrAverage said:

4) Much to my surprise, I achieved an efficiency of 82%, Is that typical or did I just get lucky?

Thanks for your help.

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That's about my average. (80 - 85%) In fact, I've been thinking lately that my efficiency may be a little too good. I'm kind of worried about extracting tannins, but I'm not sure how one lowers efficiency.

Great answers to your questions!

My only addition is that I calculate my water addition for the mash in to be 1/2 my total pre-boil volume. You'll get the water additions dialed in quickly. On average beers (1.055ish) I normally get 80%+ efficiency. I don't bother with preheating my cooler anymore. It's a waste of propane/hot water.

MrAverage said:

1) I preheated the cooler with 180 water, dumped that out and added the grain and the calculated volume of water at the correct temperature (164 deg). The mash temp ended up 2 degrees higher than it should have been. Any idea why that would be? Did I heat the cooler up too much?

Click to expand...

At this point we haven't started sparging yet. All we are doing with mashing. From your post, it sounds like you've mashed many times before with great results. My advise would be not change your mashing procedure just because you are going to batch sparge.

Once the mash is done, we start sparging. At the beginning of the brew session, you prepared a specific amount of water to brew with. Some of that was used in the mash. The remainder will be used to batch sparge. Evenly divide the remaining sparge water to complete your batch sparges. It usually takes me two or three runnings to reach my boil volume. It all depends on how much room is taken up by the grain.

If you are lazy like me, you'll top up your mash tun with sparge water, stir, vorlauf, and collect the runnings. Repeat if there is still some sparge water left.

If you want to put some more energy into it, you'll measure how many quarts go in each time.