Percentage of RO Water in Sparge

[dschiller]

I entered my Ward water report into Bru'n Water and I typically use 80% RO for my IPAs for the mash and adjust with minerals and lactic acid. Should I also use 80% RO water for the sparge, or is it OK to reduce that to 50%? Is it generally better to use at least 80% (or even 100%) RO water in both the mash and sparge, or is it unlikely to make much of a difference higher than X% RO? The quality of my tap water is average.

 

[day_trippr]

You could use anywhere from all RO to all tap water as long as it is treated with salts and acid as needed to prepare it for sparging.

I happen to use all RO for all my brewing needs as my well water has an residual alkalinity over 200 and I prefer not to use the amount of acid needed to bring that down to a useful level...

Cheers!

 

[Birrofilo]

For what I understand RO water is ideal for sparging, because you have no worry about the alkalinity of the water, which tends to extract tannins from the grains much more than temperature.
RO water has no alcalinity and there is no danger to extract tannins.

If you treat the water with salts that's OK but you have to keep into account the effect on flavour on the the beer from the salt addition.

Acidifying the sparge water is another option but I think that sparging with RO water is an hassle-free solution which is quite indicated for AIO kettle users like myself, with an AIO kettle the sparge water is normally not much and I think I will just go for a 5L flask RO water and that's it, one thing less to worry about.

YMMV.

 

[Beer666]

I recently stopped treating my RO sparge water and have noticed no difference to be honest so i don't bother.

 

[jcav]

I use 100% R/O water for my mash and sparge water. I acidify the strike water for the mash with lactic acid and I do add salts depending on the style of beer being brewed. I also acidify my sparge water below 5.8 ph and sometimes I have matched the same ph of the mash water. Once I forgot to acidify my sparge water and I did not notice any difference in the quality of the beer. It was not an IPA though but the beer was no different than the other times I have made it with acidified sparge water. Your results may vary but this is what I do and what I have experienced.

John

 

[VikeMan]

I use 100% R/O water for my mash and sparge water. I acidify the strike water for the mash with lactic acid and I do add salts depending on the style of beer being brewed. I also acidify my sparge water below 5.8 ph and sometimes I have matched the same ph of the mash water. Once I forgot to acidify my sparge water and I did not notice any difference in the quality of the beer. It was not an IPA though but the beer was no different than the other times I have made it with acidified sparge water. Your results may vary but this is what I do and what I have experienced.

If you are acidifying your RO sparge water, don't bother. You may have noticed that the amount of acid needed to bring RO/distilled water to a pH to match your mash is miniscule. The reason for that is that good RO water has virtually no buffering capacity. That tiny amount of acid is doing practically zilch to the pH the grain tannins are seeing.

 

[day_trippr]

"Correctamundo"

My RO system brings my ~300 TDS well water down to 10, and a mere 0.4ml of 25% PA in 12 gallons in my hlt is all it takes to drop it from the usual pH ~6.4 to pH 5.0 (not a goal, just an observation). And that's after salting the sparge liquor. It's crazy how little buffering capacity is left in RO water...

Cheers!

 

[Vale71]

If you are acidifying your RO sparge water, don't bother. You may have noticed that the amount of acid needed to bring RO/distilled water to a pH to match your mash is miniscule. The reason for that is that good RO water has virtually no buffering capacity. That tiny amount of acid is doing practically zilch to the pH the grain tannins are seeing.

Plus atmospheric CO2 is going to acidify it on its own so why waste perfectly good acid?

 

[couchsending]

Adding some Ca salts to your sparge water if using 100% RO can be beneficial. It will prevent a potential rise in pH (And consequential tannin extraction) at the end of sparge for low OG pale beers.

Otherwise add all the Ca salts that programs tell you to add to the sparge, yo the kettle.... that way all the Ca actually makes it into the fermenter.

It is often wise to check the TDS of your RO water. Depending on the source and how often the filters are changed it might not necessarily be all that RO. TDS meters aren’t expensive.

 

[Birrofilo]

Adding some Ca salts to your sparge water if using 100% RO can be beneficial. It will prevent a potential rise in pH (And consequential tannin extraction) at the end of sparge for low OG pale beers.

For what I know it is not the rise in pH which causes tannin extraction but the alcalinity in the water, the carbonates. RO water is basically free of carbonates and therefore there is no risk of tannin extraction. Besides, after a few hours that RO water is exposed to air its pH changes and is lowered to around 5,8. But pH is relevant only if there are carbonates in the water, else it doesn't matter (to my knowledge).

 

[cire]

For what I know it is not the rise in pH which causes tannin extraction but the alcalinity in the water, the carbonates. RO water is basically free of carbonates and therefore there is no risk of tannin extraction. Besides, after a few hours that RO water is exposed to air its pH changes and is lowered to around 5,8. But pH is relevant only if there are carbonates in the water, else it doesn't matter (to my knowledge).

Brewing isn't a range of parallel chemical equations without interaction. All aspects have cause and effects.

Carbonates cause pH to rise. The extraction of tannins and polyphenols begin above pH 5.6 and the higher pH, the greater the extraction. It we accept that darker beers might require some alkalinity to prevent pH being too low, then accordingly a degree of alkalinity in sparge liquor will be tolerated, when tannins will not be extracted until pH exceeds 5.6.

Calcium in sparge liquor will deposit with phosphate supplied by malt and thereby lower pH to in turn limit tannin extraction. Furthermore, some calcium so supplied will also deposit with oxalates in the grain to also prevent those from reaching the finished beer.

RO water has little alkalinity, often a virtue in brewing. RO water has little calcium content, not always virtuous.

 

[Birrofilo]

Brewing isn't a range of parallel chemical equations without interaction. All aspects have cause and effects.

Carbonates cause pH to rise. The extraction of tannins and polyphenols begin above pH 5.6 and the higher pH, the greater the extraction. It we accept that darker beers might require some alkalinity to prevent pH being too low, then accordingly a degree of alkalinity in sparge liquor will be tolerated, when tannins will not be extracted until pH exceeds 5.6.

I certainly see your point. That probably depends on the importance of sparge water in the total volume.

For those brewing techniques which require little sparge water (such as using AIO kettles which force the brewer to start with a relatively high water/grain ratio) a sparge with all RO is a no-fuss-no-problem approach, because regardless of pH, no carbonates means no tannins extraction, but on the other hand the sparge water is relatively minor.

But for those brewing techniques which require a lot of sparge water then a sparge made entirely with RO might lead to an undesirable mash pH or some other undesirable water characteristics, such as calcium content, because sparge water will be a substantial part of the total water brought to boil.

Having an AIO system, my simple strategy is "I sparge with 5 litres RO water and that's it".

 

[cire]

I certainly see your point. That probably depends on the importance of sparge water in the total volume.

For those brewing techniques which require little sparge water (such as using AIO kettles which force the brewer to start with a relatively high water/grain ratio) a sparge with all RO is a no-fuss-no-problem approach, because regardless of pH, no carbonates means no tannins extraction, but on the other hand the sparge water is relatively minor.

But for those brewing techniques which require a lot of sparge water then a sparge made entirely with RO might lead to an undesirable mash pH or some other undesirable water characteristics, such as calcium content, because sparge water will be a substantial part of the total water brought to boil.

Having an AIO system, my simple strategy is "I sparge with 5 litres RO water and that's it".

Absolutely so. Meanwhile, I mash with near minimum liquor volume and fly sparge to achieve maximum practical extraction. That requires sparging until the wort gravity is but a few points above unity and the sparge water will always contain calcium, but might or might not contain alkalinity determined by measuring pH of runnings.

 

[dschiller]

Thanks for all of the replies. Interesting comment about getting a TDS meter (yes, only about $15 on Amazon) to check how pure my grocery store RO water is (Glacier machine). Unless I followed up with a Ward water test on that RO water, I'm not sure what I'd do with the TDS measurement in terms of the adjustments I make using Bru'N Water. My original question was addressing the relative impact of using a higher % of RO water for sparge vs mash. Perhaps a related topic is the difference between 80% RO water vs 100% RO water. I'm thinking (1) if I use 80% RO for the mash I should probably just use 80% as well for sparge and not reduce that to 50%, and (2) I should just try brewing with 100% RO and see if I notice a difference. (Yes, adding minerals per Bru'N Water.)

 

[VikeMan]

Unless I followed up with a Ward water test on that RO water, I'm not sure what I'd do with the TDS measurement in terms of the adjustments I make using Bru'N Water.

A very low TDS reading would simply confirm that your RO water is "good." At that point, you're safe to pretend it's distilled water from a mash pH perspective, i.e. you wouldn't need a water report for the RO water.