Too much sparge water negative side effects

[skokott]

Beginning AG brewer here.

I've heard a lot of concern about sparging with too little volume of water.

I've also heard that you keep adding sparge water until you reach your desired wort volume in the brew kettle.

I'm having a difficult time understanding that.

Say you add (in theory 20 gallons) of sparge water. Won't that terribly dilute the wort? Say you stop when you reach 6.5 gallons in your BK, what's in the BK is going to be pretty diluted, right?

 

[Erik_Mog]

Are you batch sparging? If so, once you have drained the mash tun after the mash, you only need to sparge with enough water to reach your pre-boil volume. If you are fly sparging, I got no help lol. Take a look at this page: http://www.dennybrew.com/

 

[doug293cz]

Yes sparging dilutes the wort in the boil kettle, but it also rinses more sugar out of the grain bed. Getting more sugar into your BK from the grain increases your mash efficiency. If you mashed at 1.25 to 1.50 qt/lb, you would have wort with an SG of about 1.082 to 1.095 in the mash. This range of SG's is too high for low to medium gravity beers, so you need to dilute anyway. If you're making a barley wine or RIS, then maybe you don't want to sparge (but your efficiency will suffer.) By diluting in a way that increases efficiency (i.e. sparging) you reduce your total grain requirement to reach a specific OG.

Over sparging can be a problem if your sparge water is alkaline. In such a case (very common actually) too much sparging can raise the grain bed pH above 6, and you can start to extract tannins, which will cause astringency in the beer.

Brew on

 

[mongoose33]

In a recent brew, my first runnings were 1.087 in about 2.7 gallons. I could have probably waited for another pint or two of first runnings but I'm an impatient brewer sometimes. So I added sparge water--batch sparging--and drew off about 4 gallons of second runnings of 1.029. Total volume was about 6.75 gallons at a pre-boil gravity of about 1.050.

Post boil I was down to 1.059.

So--as long as you're not just running gallons and gallons of sparge water through, and do it incrementally, you'll get the most you can get from your mash, and end up at the right boil volume.

You are right--if you added 20 gallons of sparge water you'd dilute the wort remaining pretty badly. That's why it's done incrementally. You can figure this out ahead of time by figuring the amount of water that will be absorbed by the grain (depends on how much grain!), and adjusting from that. I use, with my grain bill, about 8 gallons total--a little over 4 gallons to start, the rest to sparge.

A couple times I've ended up with less boil volume than I wanted, so I just took some bottled (RO) water and "fly sparged" it over the grain bed to get out whatever else I could.

************

My most recent brew grain bill used almost 13 pounds of fermentables. I had an 8.5-gallon water bill, with 4.5 to start and 4 in the sparge. First runnings 1.091, second runnings 1.039, preboil gravity 1.055, postboil gravity 1.067.

I don't know if you caught it, but both the brews had first runnings in the range Doug293cg noted above.

 

[JimRausch]

To clarify, let's say that your 1st runnings come in at 2.5G and you are shooting for 6.5G in the BK. Then you sparge with 4.0G because with the sparge, there is no further absorption of water, so what goes in, comes out (plus dissolved sugars of course).

 

[mabrungard]

Then you sparge with 4.0G because with the sparge, there is no further absorption of water, so what goes in, comes out (plus dissolved sugars of course).

Plus the tannins and silicates that you leach from the grain. Oversparging can be quite damaging to your beer. While the lore is that keeping sparging water pH lower than 6 and cooler than 170F will keep you from leaching those components, I find that the most important thing is to avoid reducing the wort gravity within the mash bed to less than about 3 or 4 brix. There is a nice figure in Malting and Brewing Science showing the tendency to extract tannins is directly proportional to the reduction in runoff wort gravity. Don't do it!

Monitor your runoff gravity very closely and avoid filling the tun with too much sparging water. If you need to top of the pre-boil kettle volume, add the sparging water directly to the kettle and don't run it through the mash bed. That technique has corrected my one-time tannin problems.

 

[smyrnaquince]

For a "normal" gravity beer, do I run the chance of oversparging if I batch sparge in two sparges (half the total sparge volume each time) instead of in one sparge? Or is oversparging only a concern with fly sparging?

I typically mash at 1.5 qts/lb, then do two (half-volume) batch sparges to get to my final pre-boil volume. Now you have me wondering if i should be doing a single (full-volume) sparge instead, at the cost of (just) a couple of percentage points of extraction efficiency. As an example, the last brew that I took a final runnings SG measurement on came in at 1.013 for the second sparge, with the pre-boil (combined mash, sparge 1, and sparge 2) SG at 1.036. SG 1.013 = 3.3 brix for that last sparge, which is getting into that 3-4 brix danger zone.

 

[Ozarks Mountain Brewery]

I fly sparge and sometimes over sparge just by letting all the sugar drain out of the mash but its no big deal I just boil till I reach my starting level then add my bittering hops its never been an issue because I don't constantly heat my sparge water to 170, and my ph is 5.6 most of the time. in most cases it drops down to 150 by the end

 

[NoIguanaForZ]

Monitor your runoff gravity very closely and avoid filling the tun with too much sparging water. If you need to top of the pre-boil kettle volume, add the sparging water directly to the kettle and don't run it through the mash bed. That technique has corrected my one-time tannin problems.

How exactly does one "monitor runoff gravity?" I didn't think hydrometer readings were well suited to a continuous process.

For a "normal" gravity beer, do I run the chance of oversparging if I batch sparge in two sparges (half the total sparge volume each time) instead of in one sparge? Or is oversparging only a concern with fly sparging?

I typically mash at 1.5 qts/lb, then do two (half-volume) batch sparges to get to my final pre-boil volume. Now you have me wondering if i should be doing a single (full-volume) sparge instead, at the cost of (just) a couple of percentage points of extraction efficiency. As an example, the last brew that I took a final runnings SG measurement on came in at 1.013 for the second sparge, with the pre-boil (combined mash, sparge 1, and sparge 2) SG at 1.036. SG 1.013 = 3.3 brix for that last sparge, which is getting into that 3-4 brix danger zone.

I acidify my sparge water to around pH 5.7 (using Martin's tool, natch), keep it below 170 F, and have never had runoff with a gravity of less than 1.010 (the level at which Beersmith suggests you should quit). I have...not to my knowledge had a tannin problem, ever. While in principle you could batch sparge with a big enough volume to create tannin extraction potential, I think it's more of an issue with fly sparging. The only negative effects I've observed for darker beers are on my sleep schedule, since I tend to start brewing in the early evening and an over-batch-sparged batch takes longer to boil down. On the other hand, I did make a lovely Irish Re...Aubur...Brown once.

 

[mabrungard]

Good point about hydrometer readings. I use a refractometer for monitoring wort gravity throughout the mashing process.

 

[Stillraining]

keep it below 170 F, and have never had runoff with a gravity of less than 1.010 (the level at which Beersmith suggests you should quit). I have...not to my knowledge had a tannin problem, ever.

^this for me too.

 

[NoIguanaForZ]

Good point about hydrometer readings. I use a refractometer for monitoring wort gravity throughout the mashing process.

So like one reading every five minutes?

 

[Yooper]

So like one reading every five minutes?

For me, no, it's not that often. It depends on what the reading is. For example, if I have a large grainbill (say, 1.060 or higher planned OG), it would be tough to oversparge with my boil volume and amount of grain. So I'll take a reading when I'm about 3/4 done- if it's still plenty high (and it almost always is), I don't take another reading. If it's getting lower, say, 7 brix, I'll keep an eye. But not in 5 minutes, as that's only a couple of quarts or so.

The issue generally occurs with a smaller beer, say like a mild. You may have only 6 pounds of grain but a boil volume of 6.5 gallons for a 5 gallon batch. That is really when you run the risk of oversparging. Putting too much water through the grain can cause off-flavors (that's really what oversparging does). Stopping the sparge at 3-4 brix and topping up with water if necessary to reach your boil volume would be the way to go in this case. Of course you'd build the water addition into your recipe. Generally, my mild is an OG of 1.037, and that is one of the lowest OG beers I do.

 

[jigtwins]

Plus the tannins and silicates that you leach from the grain. Oversparging can be quite damaging to your beer. While the lore is that keeping sparging water pH lower than 6 and cooler than 170F will keep you from leaching those components, I find that the most important thing is to avoid reducing the wort gravity within the mash bed to less than about 3 or 4 brix. There is a nice figure in Malting and Brewing Science showing the tendency to extract tannins is directly proportional to the reduction in runoff wort gravity. Don't do it!

Monitor your runoff gravity very closely and avoid filling the tun with too much sparging water. If you need to top of the pre-boil kettle volume, add the sparging water directly to the kettle and don't run it through the mash bed. That technique has corrected my one-time tannin problems.

What would you recommend to those of us that use the batch sparge technique? Specifically how to keep the mash bed above the 3 to 4 brix. Maybe fly sparging is the proper route to go? Or possibly thicker mash?

 

[mabrungard]

I don't think its possible to reduce the wort gravity into the danger zone when you batch sparge. That's the beauty of that method. Its brewers that perform continuous sparging that need to pay attention to their final runoff gravity.

 

[skokott]

Not sure I understand still.

I use 0.5G / lb grain. Let's say I go to 1.0G / lb grain. Won't that reduce my wort's gravity (at least the second runnings) by 100%?

 

[doug293cz]

Not sure I understand still.

I use 0.5G / lb grain. Let's say I go to 1.0G / lb grain. Won't that reduce my wort's gravity (at least the second runnings) by 100%?

1 gal/lb (4 qt/lb) will most likely give you more pre-boil wort than you want before any sparging, so there will be no second runnings. It will reduce your first running wort gravity by 2X.

Brew on

 

[doug293cz]

I don't think its possible to reduce the wort gravity into the danger zone when you batch sparge. That's the beauty of that method. Its brewers that perform continuous sparging that need to pay attention to their final runoff gravity.

It is possible according to my simulations. Using a 6 lb grain bill with 7.3 gal of total brewing water (6.5 gal pre-boil vol), and doing a double batch sparge with equal volumes for all three run offs, gives me 2˚P (1.008) for the final run off. This is admittedly an extreme example, Pre-boil gravity is 7.9˚P, and OG is 9.3 (5.5 gal.)

Brew on

 

[Stillraining]

Being the Cowboy of the group, I just take my final running's reading like I would any other reading after the fact.
If it would be to low then it would be too late to do anything about it. I have never had reading .012 and most often they are well above that...and I always sparge twice... Nor do I get too exact with making sure my sparges are exactly the same size either...just a close approximation using the markings on my boil kettle...probably +- 1/2 gallon .

I got drug to a club meeting for the first time ever last night...Not a joiner type of person. All 3 of my bring a-long's were well received so I will probably be OK still disagreeing with half the stuff that makes the concern list here on a regular basis. This is one of those. Can it happen?, sure...but I bet its occurrence is a lot rarer then people think for most of us batch sparger's. At least if your getting good conversion anyway.

 

[skokott]

doug, not sure I follow.
I'm not talking about mash water which I would generally do 1.25qt/lb but sparging.

I would imagine doubling my sparge water would half my 2nd running gravity unless I'm fly sparging I would think.

 

[chickypad]

Beginning AG brewer here.

I've heard a lot of concern about sparging with too little volume of water.

I've also heard that you keep adding sparge water until you reach your desired wort volume in the brew kettle.

I'm having a difficult time understanding that.

Say you add (in theory 20 gallons) of sparge water. Won't that terribly dilute the wort? Say you stop when you reach 6.5 gallons in your BK, what's in the BK is going to be pretty diluted, right?

This part only applies to fly sparging. If batch sparging you are corrrect, adding a bunch of extra water that you don't need for your boil volume will dilute the runnings, and leaving all that in the mash tun will hurt your efficiency. When batch sparging you want to accurately anticipate or measure the first runnings, then sparge with only what you need to get to the boil volume.

 

[doug293cz]

Being the Cowboy of the group, I just take my final running's reading like I would any other reading after the fact.
If it would be to low then it would be too late to do anything about it. I have never had reading .012 and most often they are well above that...and I always sparge twice... Nor do I get too exact with making sure my sparges are exactly the same size either...just a close approximation using the markings on my boil kettle...probably +- 1/2 gallon .

I got drug to a club meeting for the first time ever last night...Not a joiner type of person. All 3 of my bring a-long's were well received so I will probably be OK still disagreeing with half the stuff that makes the concern list here on a regular basis. This is one of those. Can it happen?, sure...but I bet its occurrence is a lot rarer then people think for most of us batch sparger's. At least if your getting good conversion anyway.

Agree that over sparging when batch sparging is a rare occurrence. My example was just to show that it's not impossible. Not something to worry about unless you are making low gravity beers (less than about 1.045 OG) and trying to maximize efficiency with multiple sparges.

doug, not sure I follow.
I'm not talking about mash water which I would generally do 1.25qt/lb but sparging.

I would imagine doubling my sparge water would half my 2nd running gravity unless I'm fly sparging I would think.

Sorry, I didn't realize you were talking about sparge volumes. It wasn't obvious from your earlier post. When brewers mention water/grain ratios, I immediately think they are talking about strike water.

So yes, doubling the batch sparge volume will halve the sparge runnings SG.

Brew on

 

[NoIguanaForZ]

It is possible according to my simulations. Using a 6 lb grain bill with 7.3 gal of total brewing water (6.5 gal pre-boil vol), and doing a double batch sparge with equal volumes for all three run offs, gives me 2˚P (1.008) for the final run off. This is admittedly an extreme example, Pre-boil gravity is 7.9˚P, and OG is 9.3 (5.5 gal.)

Why would you DO that?!

 

[doug293cz]

Why would you DO that?!

If you were brewing and English Mild (just one style example) which has an OG range of 1.030 - 1.038, and your standard process was a 2X batch sparge (for high efficiency.) The simulation I did had a pre-boil SG of 1.0315 and an OG of 1.037.

Brew on

 

[smyrnaquince]

I recently brewed a Mild. 1.029 pre-boil. 1.036 OG. I did a double sparge, but didn't measure the SG if the final sparge. Maybe I should have.

 

[doug293cz]

I recently brewed a Mild. 1.029 pre-boil. 1.036 OG. I did a double sparge, but didn't measure the SG if the final sparge. Maybe I should have.

So, any off flavors?

Brew on

 

[smyrnaquince]

I just had one. Nothing off that I noticed.

 

[mongoose33]

I'm missing something here in the concern, though maybe my process just eliminates that concern, or it's perhaps that I'm brewing a higher gravity beer.

According to my notes, my last beer brewed had about 12.5. pounds of grain. Strike water was 4.5 gallons.

First runnings were 1.091 for about 2.5 gallons. I could have drawn off a bit more but it takes forever. So I add another 4 gallons of sparge water (batch sparging), stir for a bit, vorlauf and drain off the second runnings.

Second runnings were 1.039 for 4 gallons (all the absorbtion was done).

I'm not even CLOSE to 1.012 or 1.010 or anything like that. Am I still leaving some sugars behind? Sure I am--but I'm not a big brewery with a bottom line to be concerned with.

Maybe for fun next time I'll sparge again while boiling just to see what a third sparge would draw off the grain. But given that I've pulled off 6.5-6.75 gallons, there normally wouldn't be any point since I'm where I need to be.

FWIW, that batch, at the start of the boil, had a gravity of 1.055; post boil, 1.067.

 

[doug293cz]

I'm missing something here in the concern, though maybe my process just eliminates that concern, or it's perhaps that I'm brewing a higher gravity beer.

According to my notes, my last beer brewed had about 12.5. pounds of grain. Strike water was 4.5 gallons.

First runnings were 1.091 for about 2.5 gallons. I could have drawn off a bit more but it takes forever. So I add another 4 gallons of sparge water (batch sparging), stir for a bit, vorlauf and drain off the second runnings.

Second runnings were 1.039 for 4 gallons (all the absorbtion was done).

I'm not even CLOSE to 1.012 or 1.010 or anything like that. Am I still leaving some sugars behind? Sure I am--but I'm not a big brewery with a bottom line to be concerned with.

Maybe for fun next time I'll sparge again while boiling just to see what a third sparge would draw off the grain. But given that I've pulled off 6.5-6.75 gallons, there normally wouldn't be any point since I'm where I need to be.

FWIW, that batch, at the start of the boil, had a gravity of 1.055; post boil, 1.067.

The larger your grain bill compared to your pre-boil volume, the less you have to worry about over sparging, because your lauter efficiency will be lower. Over sparging only becomes a concern when your lauter efficiency gets very high (over about 94%.) To create a batch sparge scenario at the over sparge threshold you need something like:

Grain bill: 6.87 lb
Pre-boil vol: 6.5 gal
Total water: 7.39 gal
Sparge: 2X, 3 equal volume run offs
3rd runnings gravity: 2.56˚P (1.010 SG)
Lauter efficiency: 94.6%​

For 12.5 lb of grain with 6.5 gal pre-boil and 1X batch sparge, lauter efficiency is about 82.5% with a 2nd runnings SG of 1.033.

Your first runnings and sparge SG's seem implausibly high. To get a wort SG in the mash of 1.091 from 12.5 lb of grain and 4.5 gal of water (mash ratio of 1.44 qt/lb) would require an aggregate grain potential of about 1.040 (40 ppg), and the highest grain potential I have ever seen is 1.039. I suppose it's possible that your mash and sparge were stratified due to inadequate stirring, or there were some measurement errors involved. Your pre-boil SG and OG look fine, however.

Brew on

 

[Stillraining]

I've also heard that you keep adding sparge water until you reach your desired wort volume in the brew kettle.

I'm having a difficult time understanding that.

I'm sure you have gotten your answer to your satisfaction already...but rereading most this whole thread I just want to clarify that I am one of those you have probably read in other threads that do exactly this.." Keep sparging till I have my correct boil volume"

Just to be clear that does not mean I toss in water willy-nilly and leave any unused wort in my MLT...what is meant, is that if I'm a gallon short I would run exactly 1 gallon more water through the grains. I would not just add water to my boil kettle...That's all, no more no less. And in my case readings have never been to low. Others or YMMV

Edit1: But if I were a gallon short, Then I have done something wrong and I would want to find out what that is, as this is a sign of an incorrectly designed recipe or equipment profile.

Edit2: FWIW I find calculators such as Beer smith to be very, very accurate once you have your system dialed in...I'm rarely if ever short on my volumes....actually I'm more often prone to be ever so slightly over then under, as I use a lot of dark grains which seem to not absorb as much water as a blanket 2 row setting would have you believe. They also almost totally eliminate this whole debate/concern for batch sparger's, as in helping us/you build correctly proportioned i.e. grains to water ratio, recipes per style, which takes this all into account if you have your profiles set up correctly. Channeling during fly sparging is a whole other kettle of fish, and not part of any of my discussion with my methods as a batch sparger on this subject.

 

[Ozarks Mountain Brewery]

I'm sure you have gotten your answer to your satisfaction already...but rereading most this whole thread I just want to calcify that I am one of those you have probably read in other threads that do exactly this.." Keep sparging till I have my correct boil volume"

Just to be clear that does not mean I toss in water willy-nilly and leave any unused wort in my MLT...what is meant is that if I'm a gallon short I would run exactly 1 gallon more water through the grains. That's all no more no less. And in my case readings have never been to low. Others or YMMV

I agree, if anyone thinks that just running clear water over the grain till you get your correct volume is what they do then the recipe is wrong, most of the time my sparge still has sugar in it even when my volume is met, as a matter of fact I can make a second runnings making a 1 or 2 gallon beer most brew days so over sparging that extra gallon just adds more sugar "not plain water"

 

[Ozarks Mountain Brewery]

at the same time I think its very bad to barely have enough sparge water if using pumps because you starve the pump and as its gasping for more wort your adding oxygen into the wort before the boil. We don't need that at 170 degrees, Ive made that mistake several times and for that reason alone I always have more sparge water than I need just to keep the pump sufficiently flowing then I discard the rest when I hit my starting boil volume

 

[smyrnaquince]

I recently brewed a Mild. 1.029 pre-boil. 1.036 OG. I did a double sparge, but didn't measure the SG if the final sparge. Maybe I should have.

So, any off flavors?

I just had one. Nothing off that I noticed.

Let me update that. I had entered this mild in to a competition to get judges' comments. Comments pertinent to this discussion:

Judge 1:

• ...perhaps a bit acidc
• Is this a second-runnings beer? Perhaps a touch over-extracted if so.

Judge 2:

• ...slight phenol/plastic
• ...shows some astringency with an overly dry finish.

 

[Yooper]

Let me update that. I had entered this mild in to a competition to get judges' comments. Comments pertinent to this discussion:

Judge 1:

• ...perhaps a bit acidc
• Is this a second-runnings beer? Perhaps a touch over-extracted if so.

Judge 2:

• ...slight phenol/plastic
• ...shows some astringency with an overly dry finish.

The descriptions of astringency and a judge mentioning over-extraction are classic signs of oversparging.

phenol/plastic is more related to chlorophenols (chlorine), though.

 

[Stillraining]

at the same time I think its very bad to barely have enough sparge water if using pumps because you starve the pump and as its gasping for more wort your adding oxygen into the wort before the boil. We don't need that at 170 degrees, Ive made that mistake several times and for that reason alone I always have more sparge water than I need just to keep the pump sufficiently flowing then I discard the rest when I hit my starting boil volume

But I Have a hunch your recipe grist's are sized to account for that extra wort/sparge water volume loss needed for your system...No?

 

[doug293cz]

It is possible according to my simulations. Using a 6 lb grain bill with 7.3 gal of total brewing water (6.5 gal pre-boil vol), and doing a double batch sparge with equal volumes for all three run offs, gives me 2˚P (1.008) for the final run off. This is admittedly an extreme example, Pre-boil gravity is 7.9˚P, and OG is 9.3 (5.5 gal.)

Brew on

If you were brewing and English Mild (just one style example) which has an OG range of 1.030 - 1.038, and your standard process was a 2X batch sparge (for high efficiency.) The simulation I did had a pre-boil SG of 1.0315 and an OG of 1.037.

Brew on

I recently brewed a Mild. 1.029 pre-boil. 1.036 OG. I did a double sparge, but didn't measure the SG if the final sparge. Maybe I should have.

Let me update that. I had entered this mild in to a competition to get judges' comments. Comments pertinent to this discussion:

Judge 1:

• ...perhaps a bit acidc
• Is this a second-runnings beer? Perhaps a touch over-extracted if so.

Judge 2:

• ...slight phenol/plastic
• ...shows some astringency with an overly dry finish.

The descriptions of astringency and a judge mentioning over-extraction are classic signs of oversparging.

phenol/plastic is more related to chlorophenols (chlorine), though.

So, now we have a real life example of an over sparge when batch sparging. @smyrnaquince 's pre-boil SG was slightly lower than for my simulation, which had a final runnings SG of 2˚P or 1.008, so the real batch's final runnings would likely have been less than 2˚P.

From this we can work out a guideline for when to avoid double batch sparging in order to avoid over sparging.

To keep last sparge runnings SG greater than 3˚P (1.012), don't do a double batch sparge for pre-boil SG targets lower than 1.039 (OG ~ 1.048)

To keep last sparge runnings SG greater than 2.5˚P (1.010), don't do a double batch sparge for pre-boil SG targets lower than 1.036 (OG ~ 1.044)​

@smyrnaquince : Do you know the alkalinity of your sparge water, and did you acidify the sparge water?

Brew on

 

[smyrnaquince]

I used BrunWater to adjust my tap water. I dialed in a target sparge pH of 6.0. It had me add 0.9 ml of lactic acid to my 3.12 gallons of sparge water (split into two 1.56-gallon sparges). The total sparge volume is low because this was a 3 gallon batch (into the fermenter).

 

[skokott]

"Just to be clear that does not mean I toss in water willy-nilly and leave any unused wort in my MLT...what is meant is that if I'm a gallon short I would run exactly 1 gallon more water through the grains. That's all no more no less. And in my case readings have never been to low. Others or YMMV"

Ok got it. I guess I'm a bit slow. lol. Thanks.

 

[Ozarks Mountain Brewery]

But I Have a hunch your recipe grist's are sized to account for that extra wort/sparge water volume loss needed for your system...No?

correct, you have looses in a lot more places than people think, you have to account for those or you will always end up short

 

[Denny]

For a "normal" gravity beer, do I run the chance of oversparging if I batch sparge in two sparges (half the total sparge volume each time) instead of in one sparge? Or is oversparging only a concern with fly sparging?

I typically mash at 1.5 qts/lb, then do two (half-volume) batch sparges to get to my final pre-boil volume. Now you have me wondering if i should be doing a single (full-volume) sparge instead, at the cost of (just) a couple of percentage points of extraction efficiency. As an example, the last brew that I took a final runnings SG measurement on came in at 1.013 for the second sparge, with the pre-boil (combined mash, sparge 1, and sparge 2) SG at 1.036. SG 1.013 = 3.3 brix for that last sparge, which is getting into that 3-4 brix danger zone.

The risk of oversparguing is very slight, assuming you use the same amount of water as you would for a single sparge addition. But unless your mash tun isn't big enough to hold all the sparge water at once, you gain nothing by doing it and waste time.