Batch Sparging Question

I did a pretty exhaustive search and I still have some questions:

My basic plan is to convert a round 5gal cooler to an MLT with stainless braid, use a single infusion mash, and batch sparge into two brew kettles as I have to split the boil due to stove limitations. I figure I'll need 3.5 gallons per kettle to account for evaporation to end up with 5.5 in the fermenter.

So if ProMash tells me I need 7 gallons for sparge, can I just split that up any which way into 2 or 3 batches?

If not, how do I calculate how much water to use for each batch?

Also, is there any way to predict your OG based on the SG of your pre-boil wort? Or do you just trust the brewing software and not worry about it?

I never did like Promash for batch sparge calcs and besides it is very easy to figure out with a pencil. You will need to determine your evaporation rate in in order to hit your target volume. I think Promash is set to 17% ,mine is higher but 7 gallons is a good place to start.

The grain absorbs some water which you need account for after the mash is complete. I use .13 qt. per pound. I add this at the 60 minute mark and the water temp is 180-185. It raises the grain temp before the first running.

The second addition is just 1\2 of the needed volume of wort because the grain has already absorbed its water.

for example: 11 pounds of grain

11 * 1.25 ( qts. per lb.) / 4 = 3.4 gallons mash water
11 * .13 = 1.4 absorbtion
3.4-1.4 = 2 so you needt to add 1.5 gallon to get 3.5 which is half of 7 gallons.
2nd addition is 3.5 galllons which should get you 7 gallons.
It takes a few batches to get an idea on how your system works.

Blender:

I've seen a couple of posts on your methodology of doing a second addition of water to the mash. Where did you come up with this idea? It's very interesting.

When you do your first addition at 180 to 185 degrees at the end of 60 minutes, does it significantly raise the temperature of the mash? What temp water do you add for your sparge....same range?

Also, when you add the 3.5 gallons for the batch sparge, do you make the assumption that all of the absorbtion has already taken place in the original mash, so the 3.5 gallons of sparge water should just flow through?

What about stirring? Do you add the water, do an initial stir, and let it sit, or do you stir periodically?

Do you sparge immediately after adding the water, or do you let that sit for awhile?

How have your efficiencies worked out with this method?

Sorry for so many questions. I've had some efficiency issues with my first couple of all grains, so I'm trying desperately to work out the kinks. The posts on this board are very helpful. Your method of adding water at the end of the mash before the initial drain has caught my attention.

Blender said:

I never did like Promash for batch sparge calcs and besides it is very easy to figure out with a pencil. You will need to determine your evaporation rate in in order to hit your target volume. I think Promash is set to 17% ,mine is higher but 7 gallons is a good place to start.

The grain absorbs some water which you need account for after the mash is complete. I use .13 qt. per pound. I add this at the 60 minute mark and the water temp is 180-185. It raises the grain temp before the first running.

The second addition is just 1\2 of the needed volume of wort because the grain has already absorbed its water.

for example: 11 pounds of grain

11 * 1.25 ( qts. per lb.) / 4 = 3.4 gallons mash water
11 * .13 = 1.4 absorbtion
3.4-1.4 = 2 so you needt to add 1.5 gallon to get 3.5 which is half of 7 gallons.
2nd addition is 3.5 galllons which should get you 7 gallons.
It takes a few batches to get an idea on how your system works.

Click to expand...

This technique looks great except with a 5 gal cooler you may have to divide your 7 gal by 3 to get the sparge water to fit along with your grains. This means you will drain the MLT 3 times instead of 2. Low gravity or partial mash beers may work with just two runnings. I found this out with my first AG in a 5gal cooler. I had planned on just doing two runnings with 11.5lbs of grain but even filling the cooler to the top, I had less than 5 gal after 2 runnings. The third runnings gave me a little over 7 gals. This was more than I planned on but my efficiency was better than anticipated so I was only a little under with my target OG.
Craig

CBBaron said:

This technique looks great except with a 5 gal cooler you may have to divide your 7 gal by 3 to get the sparge water to fit along with your grains. This means you will drain the MLT 3 times instead of 2. Low gravity or partial mash beers may work with just two runnings. I found this out with my first AG in a 5gal cooler. I had planned on just doing two runnings with 11.5lbs of grain but even filling the cooler to the top, I had less than 5 gal after 2 runnings. The third runnings gave me a little over 7 gals. This was more than I planned on but my efficiency was better than anticipated so I was only a little under with my target OG.
Craig

Click to expand...

Yeah, I figure it will take 3 runnings, but I don't have space in my apartment for the larger cooler. I also figure I'll have to do PM for any big beers, although I don't typically make beers over 1.067ish, just my wee heavy. In some regards this hobby epitomizes the old saying, necessity is the mother of all invention (guess it all depends on what you mean by necessity).

Another question, how long does it typically take to get a system dialed in? I don't want to have too many batches go awry while I'm figuring out evaporation and efficiency rates.

It took me two batches and running an evaporation-per-hour test with water to get my numbers right. The numbers changed again (to higher efficiency) once I went to doing full boil and was doing longer sparges as a result.

davarm said:

Blender:

I've seen a couple of posts on your methodology of doing a second addition of water to the mash. Where did you come up with this idea? It's very interesting.
I got most of my information from here....http://hbd.org/cascade/dennybrew/


When you do your first addition at 180 to 185 degrees at the end of 60 minutes, does it significantly raise the temperature of the mash? What temp water do you add for your sparge....same range?
It doesn't quite get it to 165 but close, it also depends on how much water is added.

Also, when you add the 3.5 gallons for the batch sparge, do you make the assumption that all of the absorbtion has already taken place in the original mash, so the 3.5 gallons of sparge water should just flow through?
Yes
What about stirring? Do you add the water, do an initial stir, and let it sit, or do you stir periodically?
I stir at the beginning only, then again when I add the water at the end of the mash.
Do you sparge immediately after adding the water, or do you let that sit for awhile?
I let it sit for 5 minutes or so.
How have your efficiencies worked out with this method?
I am getting around 75%
Sorry for so many questions. I've had some efficiency issues with my first couple of all grains, so I'm trying desperately to work out the kinks. The posts on this board are very helpful. Your method of adding water at the end of the mash before the initial drain has caught my attention.

Click to expand...

Keep at it you will get better.

So far, I've tried to not think too hard about the volumes. With batch sparging, you can compensate real time.

First, figure out how thick/thin you want your mash. My last batch had an 8lb grain bill and I went a little thin at 1.5qt/lb so I knew my first infusion would be 12qts or 3 gallons. Heat 3 gallons to 185, pour into MLT and check the temp. If it's not already down near 170, I wait with the lid off until it is. Then I add the grain, mix well, and verify if I hit the target mash temp. If not, use small additions of boiling or cold water to compensate.

Everyone's grain absorbtion and MLT deadspace is different. I put 3 gallons in and got a little over 2 gallons out. I mean, it slows to a trickle at the end so you have to decide when enough is enough and close the valve. I knew I wanted at least 7 gallons preboil, so I needed to sparge with 5 gallons. I have the room in the MLT for the full 5 and I also have enough kettle volume to get all 5 gallons of sparge water up to temp at the same time so that's what I do. You can break the batch sparges into equal sizes or not. The only thing that I don't like is sparging with a tiny bit of water because it doesn't fully saturate the grainbed to pull the sugars.

Add your first sparge infusion (hopefully hot enough to hit a 168F grainbed temp), mix well and wait 5-10 minutes. Drain and repeat. I suggest heating up more sparge water than you think you need so you can always add a little more if necessary.

Blender said:

The grain absorbs some water which you need account for after the mash is complete. I use .13 qt. per pound. I add this at the 60 minute mark and the water temp is 180-185. It raises the grain temp before the first running.

The second addition is just 1\2 of the needed volume of wort because the grain has already absorbed its water.

for example: 11 pounds of grain

11 * 1.25 ( qts. per lb.) / 4 = 3.4 gallons mash water
11 * .13 = 1.4 absorbtion
3.4-1.4 = 2 so you needt to add 1.5 gallon to get 3.5 which is half of 7 gallons.
2nd addition is 3.5 galllons which should get you 7 gallons.
It takes a few batches to get an idea on how your system works.

Click to expand...

I need to ask for clarification here, 'cause I, too, am just starting to get things clear in my head, before I go AG.

But since the absorption of the grain is LOST from the boil volume, being retained IN the grain, is the line in bold supposed to be an ADDITION equation? So, 4.8 gallons, losing 1.4 gallons to the grain, once, and then 3.5 gallons (or actually 3.6 gallons) to get to a pre-boil volume of 7 gallons?

Henry Hill said:

I need to ask for clarification here, 'cause I, too, am just starting to get things clear in my head, before I go AG.

3.4-1.4 = 2 so you needt to add 1.5 gallon to get 3.5 which is half of 7 gallons.

But since the absorption of the grain is LOST from the boil volume, being retained IN the grain, is the line in bold supposed to be an ADDITION equation? So, 4.8 gallons, losing 1.4 gallons to the grain, once, and then 3.5 gallons (or actually 3.6 gallons) to get to a pre-boil volume of 7 gallons?

Click to expand...

No , the equation is correct. You mash with 3.4gal. 1.4gal is absorbed in the grains so if you just drain the mash tun you will get 2gal. However it is best to drain half your total volume on the first runnings so you need to add 1.5gal to the mash before draining. This water can be used to raise your grain temps up to 168-170F for a mashout.
Then you will add another 3.5gal to the tun for the second runnings.

Craig

As far as how long it will take to dial in your system: I plugged ina 65% efficiency into beesmith as a guess, for a 5.25 gallon batch. I did almost exactly what blender did and got my exact OG for 65% and 5.25 gallons, first try, its pretty simple process. NOw if i do everything the same again i know exactly what the outcome will be (hopefully).

CBBaron said:

No , the equation is correct. You mash with 3.4gal. 1.4gal is absorbed in the grains so if you just drain the mash tun you will get 2gal. However it is best to drain half your total volume on the first runnings so you need to add 1.5gal to the mash before draining. This water can be used to raise your grain temps up to 168-170F for a mashout.
Then you will add another 3.5gal to the tun for the second runnings.

Craig

Click to expand...

Okay, I think we are saying the same thing, but this is mashing in with 3.4, then adding 1.4 instead of just mashing in with 4.8?

Henry Hill said:

Okay, I think we are saying the same thing, but this is mashing in with 3.4, then adding 1.4 instead of just mashing in with 4.8?

Click to expand...

No you add 3.4gal of water to the grains for the mash. This has to rest for about 60min. Then you add an additional 1.5gal of water. Stir the mash, let sit for 10 min, recirculate some of the wort to clear the runnings then drain the entire tun.
Then for the second runnings you add another 3.5gal to the tun, stir, wait 10, recirculate, and drain.
The dry grains will absorb 1.4gal. leaving you with 2 free gallons in the mash tun at the end of the mash. Because you want to drain half of your preboil volume for the first runnings you need to add an additional 1.5gal to the tun. This means you will drain the 2 free gallons plus the additional 1.5gal for 3.5 total.
If you mash with the 4.9gal then your mash will be too thin for most efficient enzyme conversion. The enzymes have to come into contact with the starches. If there is too much water the enzymes are too dilute.

If you are like me and do big beers in a small mash tun then you can split the 7 gal total runnings into 3 even drainings so that the grain plus water volume will fit in your tun. In this case the 3.4gal mash water and 1.4 grain absorption does not change but your target runnings per batch is 7/3 or 2.33gal. This means you only need to add and additional 1/3gal at the end of the mash. But you will add two more sparges of 2.33gal to get your total 7gal preboil volume.

Craig

Henry Hill said:

Okay, I think we are saying the same thing, but this is mashing in with 3.4, then adding 1.4 instead of just mashing in with 4.8?

Click to expand...

I think you have it and CBBaron is explaining it well. Remember just to mash with your selected ratio of water to grain. I use 1.25 qts. per pound. After that you can figure out the absorbtion. I forgot to mention deadspace in your cooler. You may need to determine this and factor it in your calcs. Add this water at the end of the 60 minute mash.