Water salts when sparging

[agentbud]

I am used to doing full volume BIAB brewing and know how to calculate water additions that way. I may start doing some brews that will involve sparging. How is the water treatment different when doing full volume vs mash with sparge. Is it best to treat all the water first, then divide it up for mash and sparge or is the sparge water treated differently than the mash water? Specifically for salt additions as well as Ph adjustments? Any pointers are appreciated.

 

[mabrungard]

Having salts in your sparging water isn’t imperative, but you do need to account for whatever you do. The main thing that you have to do is make sure the alkalinity of your sparging water is properly low.

 

[aceluby]

I treat and heat up the full water to strike temp and then take the sparge water out before adding grains

 

[hawkwing]

It’s ok to add all the salts to the mash water and skip the sparge water. It’s a pain to do them separate and annoying when the software can’t do a single combined addition.

 

[MicroMickey]

As the OP stated, prepare ALL of your brewing water first before dividing it between mash and sparge. I always treat my sparge water to about 5.7 pH so I don't have problems with astringency.
see Astringency

 

[DBhomebrew]

Preparing all water as one is merely one way to achieve your goals.

I treat my very soft tap water three times with different purposes each time.

1 - Strike water with Ca salts for proper mash pH. I add CaCl and CaSO4 to the mash water keeping my eye on the mash pH and overall water profile readouts on my software of choice. Once/If the ions hit their target and the pH is still too high, I add phosphoric acid.

2 - Sparge water with a touch of phosphoric acid to prevent astringency. Just enough to bring it to 5.5 or so. My water has practically no alkalinity.

3 - Remaining Ca salts with a bit of NaCl in the kettle to complete the overall water profile for yeast health, clarity, and flavor.

 

[CascadesBrewer]

Does the type of sparging process impact this? Say a fly sparge, batch sparge, simple pour over, or dunk sparge? I mostly do full volume mashing, but once and a while I need to sparge. I usually do a dunk sparge in a bucket or pot (which is fairly similar to a batch sparge, but I usually only use a gallon or two of water). I have tended to only adjust the mineral levels and pH of my mash water.

 

[DBhomebrew]

Does the type of sparging process impact this? Say a fly sparge, batch sparge, simple pour over, or dunk sparge? I mostly do full volume mashing, but once and a while I need to sparge. I usually do a dunk sparge in a bucket or pot (which is fairly similar to a batch sparge, but I usually only use a gallon or two of water). I have tended to only adjust the mineral levels and pH of my mash water.

Yes. A fly or triple dunk/batch sparge will be more likely to raise pH than a single dunk/batch. That's one of the benefits we get by passing on a handful of efficiency points.

Given that and my near-zero alkalinity, I'm sure I could skip my sparge acidification.

 

[agentbud]

Does the type of sparging process impact this? Say a fly sparge, batch sparge, simple pour over, or dunk sparge? I mostly do full volume mashing, but once and a while I need to sparge. I usually do a dunk sparge in a bucket or pot (which is fairly similar to a batch sparge, but I usually only use a gallon or two of water). I have tended to only adjust the mineral levels and pH of my mash water.

I also normally do full volume mashing (BIAB) but I am thinking about getting a brewzilla and the 35L version is not big enough to do full volume on bigger beers so I need to study up on sparging...

 

[mabrungard]

I see these recommendations to produce a single water batch and split it into mashing and sparging additions. Unfortunately, that approach can produce substantial problems since the needs for mashing and sparging water chemistry are typically quite different. That’s the reason that there are separate calculators in Bru’n Water software to help brewers get both right for every brew.

 

[bailey mountain brewer]

I treat my mash water with acid and salts, then I treat my sparge water with just acid to get my alkalinity in check. Depending on the beer style I will add more salts to the kettle. I do this because of my setup, I don't need all my 25 gallons that are in my hlt to be treated with salts, just acid, certain styles of beer will then get added salts in the boil to account for the extra water from the sparge.

 

[ScrewyBrewer]

I use untreated RO water for sparging. That way, the pH of the mash will remain unchanged after sparging. And it is easy to do.

 

[DBhomebrew]

As the OP stated, prepare ALL of your brewing water first before dividing it between mash and sparge. I always treat my sparge water to about 5.7 pH so I don't have problems with astringency.
see Astringency

So, you treat all your water as one. Then you treat the sparge water again?

 

[hawkwing]

I use untreated RO water for sparging. That way, the pH of the mash will remain unchanged after sparging. And it is easy to do.

Dilution will change the pH won’t it?

 

[MicroMickey]

When you sparge, the water rinses out the sugars and the buffers which set the pH in the mash. As the buffers are rinsed from the mash, the mash pH will rise to the level of the sparge water. When the contents of the mash tun rise to 5.9 or above, the polyphenols (tannins) will start leaching out of the mash and into the kettle. Acidifying the sparge water doesn't do anything to the mashing as it is complete by the time you start sparging.

 

[VikeMan]

When you sparge, the water rinses out the sugars and the buffers which set the pH in the mash. As the buffers are rinsed from the mash, the mash pH will rise to the level of the sparge water.

Sort of. The sparge water mixes with the wort and the pH ends up somewhere in between the pH of the mash and the pH of the sparge water. Exactly where it will end up depends on the relative buffering capacities of the wort and the sparge water. With fly sparging, the highest combined pH will be seen at the end, when the ratio of sparge water to wort is highest. But the pH of the wort/water mixture in the mash tun will never reach the sparge water pH.

When the contents of the mash tun rise to 5.9 or above, the polyphenols (tannins) will start leaching out of the mash and into the kettle.

Again, sort of. Grain derived tannins are in every beer. It's one of the things that makes beer taste and feel like beer. The higher the mash and/or sparge pH, the more tannins. The higher the temperature, the more tannins. But there are no magic cuotoffs (like pH 5.9 and/or 170F) below which tannins are not extracted.

 

[DBhomebrew]

Dilution will change the pH won’t it?

With RO sparge water, nope. RO has zero alkalinity and therefore no ability to shift the grist's pH.

On a motorcycle forum, we explain horsepower as the speed at which you hit a wall. Torque is how far through the wall your momentum takes you.

Your sparge water can have a very pH (horsepower), but with no alkalinity (torque) it has barely any effect on the grist pH.

 

[VikeMan]

With RO sparge water, nope. RO has zero alkalinity and therefore no ability to shift the grist's pH.

It's safe to think of it this way. But technically, diluting with pure water does raise the pH ever so slightly. If the wort were composed of strong acids (which it's mostly not), it would be easy to calculate how much, and the answer would be consistent with "a very small amount of pH change unless adding a lot of water." With real-life wort, it's safe to pretend that there's no change, which is why mash pH calculators safely ignore it.

 

[agentbud]

Damn, just when I finally got a grip on water, I had to go and ask this question. I do use RO water so what I am hearing from some (maybe not all) is that I can treat my mash water (salts and Ph adjustments) and then use straight RO water for sparge and I "should" be ok. Any naysayers out there on this plan of attack? If so, please explain.

 

[VikeMan]

Damn, just when I finally got a grip on water, I had to go and ask this question. I do use RO water so what I am hearing from some (maybe not all) is that I can treat my mash water (salts and Ph adjustments) and then use straight RO water for sparge and I "should" be ok. Any naysayers out there on this plan of attack? If so, please explain.

Keep in mind that the straight RO water used for the sparge will dilute the concentrations of the ions of the brewing salts added to the mash. IOW, pay attention to the "overall" ion concentrations displayed in the brewing/water software of your choice. It's definitely okay to add salts to the kettle to compensate for that dilution if the overall concentrations would otherwise be lower than what you want.

 

[ScrewyBrewer]

Dilution will change the pH won’t it?

Not so when sparging with 100% RO water. Since it has relatively, zero pH buffering compared to the pH buffering strength of the mash.

 

[VikeMan]

Not so when sparging with 100% RO water. Since it has relatively, zero pH buffering compared to the pH buffering strength of the mash.

But.... as previously mentioned, dilution does change pH. It's just not enough to worry about, or indeed try to predict.

 

[Silver_Is_Money]

For the case of doubling the volume of water via adding distilled water in the face of near zero buffering (sans for the H+ ions required whereby for the initial body of water, before doubling, to reside at around 5.2-5.6 pH) one witnesses a pH rise of 0.3 pH points. One would need to dilute ten-fold whereby to see a 1 point rise in pH.

But alas, a mash is massively buffered by comparison, so doubling its volume by adding distilled water hardly moves the pH detector needle at all.

 

[Silver_Is_Money]

Let's take the case of 5 gallons of DI water which has been acidified with HCl to a starting pH of 5.4.

10^-5.4 = 0.000003981 molar in H+ ions

Now if we double this to 10 gallons with distilled water we cut the H+ ions in half, achieving 0.0000019905 molar in H+ water.

Now we convert back to pH and find that:

pH = −log(0.0000019905) = 5.701

 

[Silver_Is_Money]

One means to express how immovable a buffered grist pH is in the face of DI water dilution is to consider that to move a 5 Kg. grist with a DI_pH of 5.701 and a BC of 34 mEq/Kg_pH which is being mashed in DI water to pH 5.40 requires the addition of nominally (without factoring in the DI mash water at all):

Delta_pH = mEq/(Kg. x BC)
(5.701 - 5.40) = mEq/(5 x 34)
0.301 = mEq/(170)
mEq = 51.17

At pH 5.4 the weak acid known as 88% Lactic Acid has an effective acid strength of 11.451 mEq/mL

So:

51.17 mEq required ÷ 11.451 mEq/mL = 4.47 mL of 88% Lactic Acid addition rquired

From above we have already determined (albeit in reverse) that a change in molar H+ ions on the order of 0.0000019905 moles/L will move the DI waters pH by the same 0.301 pH points. 0.0000019905 moles per Liter = 0.0019905 mEq/L of H+.

5 gallons of DI mash water = 18.927 Liters.

18.927L x 0.0019905 mEq/L = 0.03767 mEq of acid required to move 5 gallons of DI water from pH 5.701 to pH 5.40

0.03767 mEq ÷ 11.451 mEq/mL = 0.00329 mL of 88% Lactic Acid (or about 1/15th of a drop)

So while diluting 5 gallons of DI water to 10 gallons has the same 'effective' impact as removing 0.00329 mL of 88% Lactic Acid (or about 1/15th of a drop), to raise our example grist infused pH 5.40 Wort by the same 0.301 pH points requires the equivalent of removing 4.47 mL of Lactic Acid from the Wort.

4.47/0.00329 = 1,358.7 (with this effectively being the magnitude of the grist buffering vs. DI water buffering)

 

[Silver_Is_Money]

pH is merely a base 10 exponent.

A shorthand means whereby to discover the degree of pH shift induced upon DI water which has been "strong acid" acidified, or "strong base" caustified, is to pick the pH shift desired and raise 10 to it.

Example:

We have already noted that the pH shift for strong acid acidified DI water for the case of doubling it's volume with 7.00 pH neutral DI water is 0.301 pH points, so therefore:

10^0.301 = 1.99986187 (or a volume doubling)

Example #2:

We have already expressed that the pH shift for strong acid acidified DI water for the case of diluting it's volume 10-fold with 7.00 pH neutral DI water is 1 pH point, so therefore:

10^1 = 10 (or a volume increase of 10X)

 

[Silver_Is_Money]

Let's say that you've accidentally over acidified your sparge water to pH 4.8 while attempting to bring it to pH 5.4. And you want to bring it back to pH 5.4 via dilution with DI water.

5.4 - 4.8 = 0.6

10^0.6 = 3.981

Quadrouple (4X) the volume of your sparge water via the addition of DI water and you will restore it to the originally desired pH of 5.4. Or alternately take one fourth of your water and restore that to your originally desired sparge water volume via adding more DI water...

10^-0.6 = 0.251

 

[whattabrau]

Sort of. The sparge water mixes with the wort and the pH ends up somewhere in between the pH of the mash and the pH of the sparge water. Exactly where it will end up depends on the relative buffering capacities of the wort and the sparge water. With fly sparging, the highest combined pH will be seen at the end, when the ratio of sparge water to wort is highest. But the pH of the wort/water mixture in the mash tun will never reach the sparge water pH.

However, it's important to keep in mind that the runoff wort pH in fly sparging isn't the deciding factor. The pH where the grains are most rinsed is the deciding factor, and that location is at the top and like you point out towards the end. The pH in that subsection of the lautertun will approach the sparge water pH, because there's nothing from the mash left to rinse. One way to verify the difference is to taste the spent grains towards the top and the bottom.

edit: and just to be very clear, the above applies only to fly sparging

 

[VikeMan]

However, it's important to keep in mind that the runoff wort pH in fly sparging isn't the deciding factor. The pH where the grains are most rinsed is the deciding factor, and that location is at the top and like you point out towards the end. The pH in that subsection of the lautertun will approach the sparge water pH, because there's nothing from the mash left to rinse. One way to verify the difference is to taste the spent grains towards the top and the bottom.

edit: and just to be very clear, the above applies only to fly sparging

Yeah, but I'd add that there is never "nothing" left in the mash. If there were, we'd get 100% mash efficiency. Also, although we typically talk about high pH as being a driver of excessive tannin extraction, and I'm as guilty as anyone in that regard, I believe it would be more accurate to talk about alkalinity (which distilled water has none of). Here is an interesting read on the subject:

Sparge Water Acidification

@mabrungard, thoughts?

 

[whattabrau]

Yeah, but I'd add that there is never "nothing" left in the mash. If there were, we'd get 100% mash efficiency. Also, although we typically talk about high pH as being a driver of excessive tannin extraction, and I'm as guilty as anyone in that regard, I believe it would be more accurate to talk about alkalinity (which distilled water has none of).

There's never "nothing" in the mash *on average*, but my point was exactly that the average does not count.

Also, I don't think it's accurate to talk about alkalinity, assuming harshness is extracted as a function of pH. You still need 10^-5 mol of H+ to drop the pH of distilled water to 6. You just need more H+ if your water has non-zero alkalinity to neutralize.

 

[VikeMan]

There's never "nothing" in the mash *on average*, but my point was exactly that the average does not count.

Seriously, there's never "nothing" in the mash ever, not just on average.

Also, I don't think it's accurate to talk about alkalinity, assuming harshness is extracted as a function of pH. You still need 10^-5 mol of H+ to drop the pH of distilled water to 6. You just need more H+ if your water has non-zero alkalinity to neutralize.

The fact that you need more H+ to neutralize when the water has non-zero alkalinity nicely demonstrates why it's the alkalinity that's important, I think. Do we really think that adding 0.005 ml of lactic acid to 5 gallons of distilled water has any real impact, even though it reduced the water's pH to 5.5 (or whatever)? I mean, there is almost no buffering capacity in that acidified water.

Anyway, I'd recommend reading the paper I linked, and hopefully @mabrungard will comment.