Partial mash / sparge / salts?

[agentbud]

Been brewing 10 years or so. First 5 or 6 using extract and the rest as BIAB. Every brew I have done has always been full volume mash/boil. I have never done partial or needed to sparge. I am "thinking" about getting one of the new Brewzilla Gen 4. My only concern is that I sometimes brew big beers and I worry the 9.25 gal limit would not be enough room to do a full volume mash. So, I have a couple questions:

1) When doing a partial mash (with plans to sparge to get up to full boil volume), how do you know how much water to start with in the mash? Is there a general rule like x qts per lb of grain?
2) I use RO water and add my salts in prior to mash. When sparging, do I use the same % of salts / acids (for ph) in both the mash and sparge water or do they differ?
3) When doing a full volume mash, I typically do a 10 min mash out at 170. With a partial mash/sparge, since the sparge water will be 170, is a mash out step still needed to stop conversion?

Thanks, Mike

 

[Sammy86]

1) When doing a partial mash (with plans to sparge to get up to full boil volume), how do you know how much water to start with in the mash? Is there a general rule like x qts per lb of grain?

There is a formual but I don't know it. I would definitely get on some software, Beersmith, BrewersFriend, Brewfather etc.

2) I use RO water and add my salts in prior to mash. When sparging, do I use the same % of salts / acids (for ph) in both the mash and sparge water or do they differ?

I personally don't add salts to the sparge water...you're just rinsing the grains anyway. Ph shouldn't be that much of a factor with your pour over on the Brewzilla.

3) When doing a full volume mash, I typically do a 10 min mash out at 170. With a partial mash/sparge, since the sparge water will be 170, is a mash out step still needed to stop conversion?

Again, personally don't do mash out. I really don't see the point of doing one at our level output.

 

[doug293cz]

Been brewing 10 years or so. First 5 or 6 using extract and the rest as BIAB. Every brew I have done has always been full volume mash/boil. I have never done partial or needed to sparge. I am "thinking" about getting one of the new Brewzilla Gen 4. My only concern is that I sometimes brew big beers and I worry the 9.25 gal limit would not be enough room to do a full volume mash. So, I have a couple questions:

1) When doing a partial mash (with plans to sparge to get up to full boil volume), how do you know how much water to start with in the mash? Is there a general rule like x qts per lb of grain?
...

First what you are talking about is not a "partial mash." A partial mash is when you get some of your fermentables from mashing, and the rest of the fermentables from malt extract. You are just doing a regular "all grain" mash and sparge.

The amounts of water for mashing are not particularly critical. There are two bare minimum requirements:

1. You must use enough water so that your mash will be thin enough to be easily stirred.
2. You must use enough water so that all of your grain is covered with liquid during the mash (#1 usually takes care of this.)

After that you are free to divide your total water between strike volume (for mashing) and sparge volume. When doing a pour over sparge, as is typical for Brewsilla type units, the more water you can save for sparging, the higher your mash (specifically lauter) efficiency will be. If you were doing a batch or dunk sparge, then you would want to adjust the water volumes so that you get about the same volume from the initial wort run-off and the sparge run-off. An easy rule of thumb that will accomplish this is to use 60% of your total water for mashing, and 40% for sparging (assuming 60% of your water allows you to meet criteria 1 & 2 above - it might not for a big beer.)

...
2) I use RO water and add my salts in prior to mash. When sparging, do I use the same % of salts / acids (for ph) in both the mash and sparge water or do they differ?
...

About the only thing you have to do is make sure there is enough calcium in the mash water, so that all the wort in the boil will have enough calcium for yeast health when you get to fermentation. Anything more than 50ppm should do. If 60% of your total water goes for strike, then you would want a minimum of 50ppm / 0.60 = 84ppm in your strike water, since the sparge water won't be bringing any Ca with it.

If you had water with any significant alkalinity (RO has none) you should acidify your sparge water to a pH of about 5.8, so that it cannot raise the mash pH too high when sparging.

...
3) When doing a full volume mash, I typically do a 10 min mash out at 170. With a partial mash/sparge, since the sparge water will be 170, is a mash out step still needed to stop conversion?

Unless you are worried about your wort becoming too fermentable, there is no reason to do a mash out. But then, since you can just start heating the boiler while you are sparging, that will have the same effect as a mash out.

Some brewers do see an increase in mash efficiency when they do a mash out, but that is only because their mash conversion was not complete within the allotted time. In this case, what the mash out is doing is extending the mash time, and accelerating gelatinization and enzyme action (until the enzymes are completely denatured), thus getting a higher conversion efficiency. If your conversion is already 100% complete at the end of your mash time, then you will not get any efficiency increase from doing a mash out. What's easier, extending the mash time or conducting a mash out?

Brew on

 

[hottpeper13]

What he said^. I put the salts in calculated for ppm /Gal of total brewing liquor. To maintain that using a sparge,I put the salts in the boil kettle instead of the sparge liquor.

 

[agentbud]

First what you are talking about is not a "partial mash." A partial mash is when you get some of your fermentables from mashing, and the rest of the fermentables from malt extract. You are just doing a regular "all grain" mash and sparge.

The amounts of water for mashing are not particularly critical. There are two bare minimum requirements:

1. You must use enough water so that your mash will be thin enough to be easily stirred.
2. You must use enough water so that all of your grain is covered with liquid during the mash (#1 usually takes care of this.)

After that you are free to divide your total water between strike volume (for mashing) and sparge volume. When doing a pour over sparge, as is typical for Brewsilla type units, the more water you can save for sparging, the higher your mash (specifically lauter) efficiency will be. If you were doing a batch or dunk sparge, then you would want to adjust the water volumes so that you get about the same volume from the initial wort run-off and the sparge run-off. An easy rule of thumb that will accomplish this is to use 60% of your total water for mashing, and 40% for sparging (assuming 60% of your water allows you to meet criteria 1 & 2 above - it might not for a big beer.)



About the only thing you have to do is make sure there is enough calcium in the mash water, so that all the wort in the boil will have enough calcium for yeast health when you get to fermentation. Anything more than 50ppm should do. If 60% of your total water goes for strike, then you would want a minimum of 50ppm / 0.60 = 84ppm in your strike water, since the sparge water won't be bringing any Ca with it.

If you had water with any significant alkalinity (RO has none) you should acidify your sparge water to a pH of about 5.8, so that it cannot raise the mash pH too high when sparging.


Unless you are worried about your wort becoming too fermentable, there is no reason to do a mash out. But then, since you can just start heating the boiler while you are sparging, that will have the same effect as a mash out.

Some brewers do see an increase in mash efficiency when they do a mash out, but that is only because their mash conversion was not complete within the allotted time. In this case, what the mash out is doing is extending the mash time, and accelerating gelatinization and enzyme action (until the enzymes are completely denatured), thus getting a higher conversion efficiency. If your conversion is already 100% complete at the end of your mash time, then you will not get any efficiency increase from doing a mash out. What's easier, extending the mash time or conducting a mash out?

Brew on

Excellent info. Thank you.

 

[agentbud]

First what you are talking about is not a "partial mash." A partial mash is when you get some of your fermentables from mashing, and the rest of the fermentables from malt extract. You are just doing a regular "all grain" mash and sparge.

The amounts of water for mashing are not particularly critical. There are two bare minimum requirements:

1. You must use enough water so that your mash will be thin enough to be easily stirred.
2. You must use enough water so that all of your grain is covered with liquid during the mash (#1 usually takes care of this.)

After that you are free to divide your total water between strike volume (for mashing) and sparge volume. When doing a pour over sparge, as is typical for Brewsilla type units, the more water you can save for sparging, the higher your mash (specifically lauter) efficiency will be. If you were doing a batch or dunk sparge, then you would want to adjust the water volumes so that you get about the same volume from the initial wort run-off and the sparge run-off. An easy rule of thumb that will accomplish this is to use 60% of your total water for mashing, and 40% for sparging (assuming 60% of your water allows you to meet criteria 1 & 2 above - it might not for a big beer.)



About the only thing you have to do is make sure there is enough calcium in the mash water, so that all the wort in the boil will have enough calcium for yeast health when you get to fermentation. Anything more than 50ppm should do. If 60% of your total water goes for strike, then you would want a minimum of 50ppm / 0.60 = 84ppm in your strike water, since the sparge water won't be bringing any Ca with it.

If you had water with any significant alkalinity (RO has none) you should acidify your sparge water to a pH of about 5.8, so that it cannot raise the mash pH too high when sparging.


Unless you are worried about your wort becoming too fermentable, there is no reason to do a mash out. But then, since you can just start heating the boiler while you are sparging, that will have the same effect as a mash out.

Some brewers do see an increase in mash efficiency when they do a mash out, but that is only because their mash conversion was not complete within the allotted time. In this case, what the mash out is doing is extending the mash time, and accelerating gelatinization and enzyme action (until the enzymes are completely denatured), thus getting a higher conversion efficiency. If your conversion is already 100% complete at the end of your mash time, then you will not get any efficiency increase from doing a mash out. What's easier, extending the mash time or conducting a mash out?

Brew on

Ok, BrewZilla has arrived so I am going back over my sparging notes one more time. Let me lay out an example to see if I have this right.
If I were doing full volume BIAB for a recipe using 14 lbs of grain, my software says I need to start with 8.4 Gal water to end up with a pre-boil wort volume of 7 Gal and add the following salts (starting with RO water): 9.75g Calcium Chloride, 7.8g Epsom Salt, .8g Gypsum and 3.65g Salt. And to get the mash Ph down to about 5.3 I would add 7ml 88% lactic acid.
So, if instead of doing BIAB, I use the same recipe in the brewzilla doing a mash with pour-over sparge. I would mash with about 5 Gal water and sparge with whatever amount I need to get up to my pre-boil amount of 7 Gal.. What I still do not fully grasp is how do I split up the above-mentioned salts and lactic acid across the initial strike vs the sparge waters. Sorry for rehashing this.

 

[BeerAndTele]

What I still do not fully grasp is how do I split up the above-mentioned salts and lactic acid across the initial strike vs the sparge waters. Sorry for rehashing this.

You might get some different answers here, but mine would be: if you're using RO water for your sparge, don't worry about acidifying your sparge water ... just acidify your mash water to reach your desired mash pH. With a lack of alkalinity in the RO water, the sparge won't significantly alter the pH of the wort going into the boil kettle. If you were sparging with high-alkalinity water, I'd answer differently.

Have fun with your new system!

 

[agentbud]

You might get some different answers here, but mine would be: if you're using RO water for your sparge, don't worry about acidifying your sparge water ... just acidify your mash water to reach your desired mash pH. With a lack of alkalinity in the RO water, the sparge won't significantly alter the pH of the wort going into the boil kettle. If you were sparging with high-alkalinity water, I'd answer differently.

Have fun with your new system!

so if I was originally adding 7ml lactic acid to the 8.4 gal full volume mash amount to get my desired mash ph, but I am now only mashing with 5 gal water, do i reduce the lactic acid by the same ration?

 

[BeerAndTele]

so if I was originally adding 7ml lactic acid to the 8.4 gal full volume mash amount to get my desired mash ph, but I am now only mashing with 5 gal water, do i reduce the lactic acid by the same ration?

No ... not as long as your grain bill remains unchanged.

 

[doug293cz]

so if I was originally adding 7ml lactic acid to the 8.4 gal full volume mash amount to get my desired mash ph, but I am now only mashing with 5 gal water, do i reduce the lactic acid by the same ration?

I would use a water chemistry calculator with the specifics of your batch, rather than assume linearity.

Brew on

 

[BeerAndTele]

I would use a water chemistry calculator with the specifics of your batch, rather than assume linearity.

Brew on

This is interesting. My calculator's predicted mash pH doesn't change if the mash/sparge water volume ratio changes ... only if the grainbill changes ... or the salts or acid additions change. (Using distilled water as base.)

Would you expect it to change with a mash/sparge ratio change (using RO water)? Thanks.

 

[hottpeper13]

Might you have the amounts for epson and gypsum reversed? and that's a lot of sodium.

 

[doug293cz]

This is interesting. My calculator's predicted mash pH doesn't change if the mash/sparge water volume ratio changes ... only if the grainbill changes ... or the salts or acid additions change. (Using distilled water as base.)

Would you expect it to change with a mash/sparge ratio change (using RO water)? Thanks.

I've never done that experiment myself, so I didn't know what to expect. But, the answer you got from your water software was different than your original guess of linear proportionality, so it's good that you did the calcs.

Brew on

 

[IslandLizard]

This is interesting. My calculator's predicted mash pH doesn't change [...]

Why would it, given this:

(Using distilled water as base.)

That's the key to the "riddle!" ^
Because you're not adding any minerals to compensate for your water composition, it has none. They only compensate/enhance your grist minerals, all (or most) of which are leftover in the final wort in your kettle, and going into the fermenter.