[mabrungard]

If starting with high quality RO water that has been verified to have low TDS, then the amount of hardening minerals added to the mashing water should produce an acceptable mash pH. In addition, high quality RO water should have low alkalinity and there shouldn't be a need to acidify the sparging water.

I'll repeat a favorite mantra: The difference between medicine and poison, is dose. As pointed out above, if you taste straight epsom salt or mix up a strong solution, it will taste like sh*t. Just like the rest of the minerals that we use would taste like sh*t if you performed the same test with them.

At 18 ppm Mg, there is little taste added via the epsom salt, but as pointed out, it adds a bunch of desirable sulfate. However, this not to say that any brewer should add epsom salt willy nilly. Unless you know that your starting water has very low Mg content, don't add more Mg since the upper limit for Mg is fairly low.   

I had an astringency problem like the OP and I finally found out that I was oversparging the mash and the runoff gravity was allowed to fall too low. I had been stopping at 2 brix and found that the problem went away if I stopped runoff at 3 brix.

[erockrph]

I disagree in regards to the Epsom salts. I use them in everything hoppy. There is no way to get the sulfates up so high without them.

+ 1 to mash acidification. What was your calculated mash ph?

Around 5.3 I put all the salts into the mash. I have been using Brewers Friend Water Chemistry calculator.

http://www.brewersfriend.com/mash-chemistry-and-brewing-water-calculator/

I also have used Epsom salts with success. Am I correct in assuming astringency is the nasty bitterness that lays across your tongue?

Not really. It's more like a drying sensation that you'd get from super strong tea or a big, tannic red wine. But that bitterness does sound like it could be water-related, as others have said.

It could also be hop-related. I've had that kind of nasty bitterness where I've done a big dry-hop addition and let it sit too long. Sort of like chewing on a raw hop cone versus a proper IPA-type bitterness. In that case, some cold conditioning time may help clear that up a bit.

[bustdbrewing]

Another issue could be that the area you live had its water source changed/moved according to some sort of seasonal issue.  So your old water report becomes defunct and you are essentially adding blindly.

Jeff

Good point. I read his post as using RO, but maybe he is diluting tap water with RO

I probably missed that part.  If he is making his own RO tho he may need a membrane change etc etc.

Sorry I forgot that part. I am using RO water from the local grocery store. The water that comes out of my tap is high in alkalinity.. The range given on the water report is 300-600 CaCO3. Plus it also has chloramine so I started using straight RO.

What I have done in the past was heat up some RO water toss the grain in and then add the salts and stir it up to get it circulating. Should I be putting all my water into one vessel and treating it there then disbursing it to the proper kettle?

[Stevie]

Martin -- What about us batch spargers? Trial and error? Batch sparge with less and add water to the kettle?

[bustdbrewing]

I disagree in regards to the Epsom salts. I use them in everything hoppy. There is no way to get the sulfates up so high without them.

+ 1 to mash acidification. What was your calculated mash ph?

Around 5.3 I put all the salts into the mash. I have been using Brewers Friend Water Chemistry calculator.

http://www.brewersfriend.com/mash-chemistry-and-brewing-water-calculator/

I also have used Epsom salts with success. Am I correct in assuming astringency is the nasty bitterness that lays across your tongue?

Not really. It's more like a drying sensation that you'd get from super strong tea or a big, tannic red wine. But that bitterness does sound like it could be water-related, as others have said.

It could also be hop-related. I've had that kind of nasty bitterness where I've done a big dry-hop addition and let it sit too long. Sort of like chewing on a raw hop cone versus a proper IPA-type bitterness. In that case, some cold conditioning time may help clear that up a bit.

That is a better description of what it is. I do not have many advanced homebrewers in my area so I'm learning this stuff as I go

[bustdbrewing]

If starting with high quality RO water that has been verified to have low TDS, then the amount of hardening minerals added to the mashing water should produce an acceptable mash pH. In addition, high quality RO water should have low alkalinity and there shouldn't be a need to acidify the sparging water.

I'll repeat a favorite mantra: The difference between medicine and poison, is dose. As pointed out above, if you taste straight epsom salt or mix up a strong solution, it will taste like sh*t. Just like the rest of the minerals that we use would taste like sh*t if you performed the same test with them.

At 18 ppm Mg, there is little taste added via the epsom salt, but as pointed out, it adds a bunch of desirable sulfate. However, this not to say that any brewer should add epsom salt willy nilly. Unless you know that your starting water has very low Mg content, don't add more Mg since the upper limit for Mg is fairly low.   

I had an astringency problem like the OP and I finally found out that I was oversparging the mash and the runoff gravity was allowed to fall too low. I had been stopping at 2 brix and found that the problem went away if I stopped runoff at 3 brix.

Martin,

If the brix is getting that low wouldn't that mean your efficiency would be high or am I interpreting that incorrectly? Is the brix reading temperature corrected?

[denny]

Am I correct in assuming astringency is the nasty bitterness that lays across your tongue?

Nope.  Astringency is a dry mouthfeel, like sucking on a used tea bag or grape skin.

[denny]

Martin -- What about us batch spargers? Trial and error? Batch sparge with less and add water to the kettle?

Not necessarily.  You really can't make a blanket decision like that.  You need to monitor your sparge pH and do what needs to be done.  with my water, for instance, there's no problem so no need to adjust technique.

[Stevie]

Martin -- What about us batch spargers? Trial and error? Batch sparge with less and add water to the kettle?

Not necessarily.  You really can't make a blanket decision like that.  You need to monitor your sparge pH and do what needs to be done.  with my water, for instance, there's no problem so no need to adjust technique.

I'm all RO, add zero salts to my sparge, and have only had astringency issues with a couple of dark beers. I imagine the contact time with fly sparging plays a role. I normally let the sparge water rest for 5 minutes and it takes another 5 or so to drain for most beers.

[markpotts]

Martin -- What about us batch spargers? Trial and error? Batch sparge with less and add water to the kettle?

First post here....so go easy on me folks 
I have had some issues with astringency, which thanks in no small part to Martins excellent spreadsheet I have banished from my brews. My own feeling is that pH plays a huge part in astringency.
I batch sparge and use Bru'nWater to calculate the mash and sparge salts. The sparge salts I divide pro-rata based on the top up volumes and sprinkle them over the mash before adding the liquor. You could also add them to the HLT, but I find the lower pH of the mash helps them dissolve better.
I also adjust my mash and sparge liquor to between 20 and 30 ppm alkalinity (from 130-140ppm using H2SO4).
By adjusting the sparge liquor alkalinity and having the right salt balance in the mash and sparge the pH is kept at a level where astringent compounds are not extracted and my beers have benefited greatly.

[mabrungard]

While I know that high pH and high alkalinity can worsen tannin and silicate extraction during sparging, I found that the gravity of the final runnings had a big part to play. It is the major factor once you have solved the pH and alkalinity issue.

Mark, I've found that the salts don't have to be added to the mash to dissolve. I think what you are experiencing is due to the minerals disappearing into the grist. They aren't necessarily dissolving any faster (out of sight, out of mind). I've found that all minerals excepting chalk will dissolve readily in the HLT...it just takes a few minutes of stirring.

Mark, I see you use sulfuric acid. What strength do you use and did you dilute it for general use? Has it been too "fuming" when you use it? That is my primary concern with sulfuric and hydrochloric acids...they produce hazardous fumes. They would be great for brewing excepting for that (all acids require careful handling and dosing, but the fume thing is another worry on top of it). 

[ynotbrusum]

Darn, I thought I had this water thing kinda figured out - read the Water book and noted that if you use RO in the sparge, there is no need to acidify and no concerns about pH in the sparge (says so right there in Chapter 5 or 6 below a chart, IIRC); so I installed an RO system, build up my water from RO for the mash and leave the sparge water alone as RO...now I see that gravity of the final runnings might still do me in on some beers!  I don't make hoppy beers too often, so I have skipped the sulfate additions for the most part.  For batch sparges on longer boils, there may be some tannins extracted, despite sparging with RO...I guess nothing is as easy as I thought.  Gonna have to get me some phosphoric acid after all.

[morticaixavier]

Darn, I thought I had this water thing kinda figured out - read the Water book and noted that if you use RO in the sparge, there is no need to acidify and no concerns about pH in the sparge (says so right there in Chapter 5 or 6 below a chart, IIRC); so I installed an RO system, build up my water from RO for the mash and leave the sparge water alone as RO...now I see that gravity of the final runnings might still do me in on some beers!  I don't make hoppy beers too often, so I have skipped the sulfate additions for the most part.  For batch sparges on longer boils, there may be some tannins extracted, despite sparging with RO...I guess nothing is as easy as I thought.  Gonna have to get me some phosphoric acid after all.

gravity of runnings is only going to be an issue with continuous spargeing still. Unless you are totally obsessed with squeezing every last drop out of your mash your runnings in a batch sparge situation will never be below 3 brix. so no worries if you batch sparge. if you ARE spargeing that much you can deal with this issue by adding an extra pound of grain and not spargeing so much!

[HoosierBrew]

gravity of runnings is only going to be an issue with continuous spargeing still. Unless you are totally obsessed with squeezing every last drop out of your mash your runnings in a batch sparge situation will never be below 3 brix. so no worries if you batch sparge. if you ARE spargeing that much you can deal with this issue by adding an extra pound of grain and not spargeing so much!

+1. Not the same concern with batch sparging. Another reason I'm glad I made the switch.

[markpotts]

Mark, I see you use sulfuric acid. What strength do you use and did you dilute it for general use? Has it been too "fuming" when you use it? That is my primary concern with sulfuric and hydrochloric acids...they produce hazardous fumes. They would be great for brewing excepting for that (all acids require careful handling and dosing, but the fume thing is another worry on top of it).

The supplier claims it is 25% sulphuric acid; however it has been reported by others that it actually 35% and from my tests I would concur that it is indeed 35%.
I also worry about the safety aspect, but I can't say there has been much fuming and I am ultra careful when  handling any acids at home.
I had not even considered dilution.....that is a great suggestion thanks.