Epsom vs. Gypsum

[SEndorf]

I have been playing with bru'n water to adjust my RO water and have been thrilled with this tool.
Question - any comments or concerns replacing gypsum with epsom salt?

Epsom appears to bump the sulfates with a small impact to magnesium.
Gypsum bumps the sulfates AND cal chloride, which I don't need.

What would be the difference at bottle opening time?

Thanks

 

[schematix]

Not quite...

Gypsum bumps Calcium AND Sulfate.

Epsom is Magnesium AND Sulfate.

Epsom salt gives 26ppm of Mg and 103 ppm Sulfate per gram per gallon.

Gypsum gives 61ppm of Calcium and 147ppm Sulfate per gram per gallon.

You typically don't want Mg levels really high so there is a practical limit as to how much you can use.

I keep calcium chloride, pure sodium chloride, epsom salt, gypsum and chalk in my mineral inventories so I can make pretty much all adjustments I need.

 

[SEndorf]

Yes.
I'm looking at small amounts to tweak an English bitter.
0.5 g. / gal. of Epsom gives me 52 ppm sulfates / 13 ppm magnesium
I'm wondering if Epsom in lieu of gypsum will change the flavor.

 

[schematix]

Are you using 100% RO water or are you diluting? If diluting, what does your stock water profile look like?

 

[SEndorf]

100 RO water. My tap water is disastrous.

 

[schematix]

OK if you're starting with RO/distilled then you need to make sure you have some other ions present.

There are some other threads on HBT that deal with the water profile for this style. Google "english bitter water profile" and you'll get some matches.

Why do you want to swap out epsom for gypsum? If you're starting with RO water you really need to have a pretty good range of ions to get the beer into the right range (unless you're doing a true Pilsen lager).

I'd probably do something along these lines:
Gypsum - 0.32g/G
Epsom - 0.6g/G
NaCl - 0.1g/G
CaCl2 = 0.3 g/G
Chalk = 0.15 g/G (all in the mash)

This gives 57ppm Ca (50 is a good minimum for yeast health), Mg = 15, Na = 10, SO4 = 109 (for bitterness), Cl = 54 (for malt sweetness) and CO3 = 48 (mash pH).

This is a guideline but in general most beers don't do great with really pure water because of the mash pH and the lack of minerals leads to a duller beer.

 

[ajdelange]

Yes, replacing gypsum with epsom salts will have a disastrous effect in most cases because whereas calcium (in gypsum which is calcium sulfate) is pretty flavor neutral magnesium (in epsom salts which is magnesium sulfate) has, at appreciable concentration, an unpleasant, sour bitter taste.

When using RO water it is usually sufficient to use either just calcium sulfate or calcium chloride or a mix depending on the beer you are making. See the Primer.

Note: you do not need a minimum of 50 mg/L Ca++ for yeast health: lots of great beers are made with half that or less. Calcium does have benefits though.
Note 2: Never add chalk to mash water or mash. Chalk is an alkali. In most beers you will need acid. In the cases where you do need alkali (dark beers) chalk is a poor choice. Use lime or sodium bicarbonate instead.

 

[mabrungard]

Magnesium can certainly change the taste of the beer. I do like it in bittered beers where its character helps accentuate that component. I wouldn't typically add it to water for beers that aren't focused on bitterness and hopping. With that said, there are plenty of great brewing waters around the world that do have a modest Mg content. So it's not truly detrimental when present at low levels (<20 ppm). That level of magnesium is present in many waters across Southern Bavaria and there are many malty and delicious beers from that region. So it is reasonable to accept a low level in many brewing waters. The most important thing is that Mg quickly becomes a negative in beer flavor when present at levels over 40 ppm. Don't add it unless you really want it in your beer!

 

[SEndorf]

This is how I adjusted a strong english bitter, currently fermenting:
0.50 g. / gal epsom
0.25 g. / gal calcium chloride
0.25 g. / gal pickling lime

Finished profile:
54.7 calcium
13.0 magnesium
8.0 sodium
52.5 sulfate
35.9 chloride
PH 5.4

Martin and AJ, I seek out your writings and comments whenever I can find them. I wanted to try a low dose of magnesium specifically for this bitter. I'm still in the noob category, but the adjustments made in the last several batches have made some truly remarkable beers (with a few bumps along the way.)
If I understand correctly, a very low magnesium level can be desirable depending on the beer profile.
Given the above, would you recommend any changes?
Also, RO water has an advantage in that we're all starting basically from the same point. In addition to Bru'n water's profiles, are there any resources available for suggested water adjustments for specific brews with 100% RO water?

 

[ajdelange]

A small amount of magnesium in the water won't hurt but then again it won't do much of anything for you either as the malt itself is an adequate source for magnesium in terms of coenzyme duty. Most people thus, unless seeking the flavor (and or other) effects of magnesium, don't bother to supplement it. It always sort of bothered me that when you buy a pound of epsom salts you are paying for half a pound of water but then, given that you can buy a pound at the pharmacy for a couple of bucks that doesn't much matter.

What you have should be a good starting point as there is no long pole in the tent. The sulfate level is much lower than what most people would probably use but I think you are smart to start off this way. When the beer is finished taste it with additional sulfate (gypsum) added in small quantities to the glass. If you think this improves the beer then brew it with additional sulfate in the future. If you don't then don't augment the sulfate.

As to other sources for water treatments: I think people way over do this idea that to brew a Stout you have to have Dublin water. The people that originally brewed stout in Dublin used Dublin water for obvious reasons and it doubtless had an influence on what Irish stout is like but you don't have to duplicate it at all to get a good stout. Any nominal water will do. RO with some calcium chloride and, if you like it, calcium sulfate will do. What does best is the beer that most pleases the brewer by whatever his optimality criterion is. If that is authenticity then you might want to try to find out about the water a Dublin brewery actually used and how they treated it. If the criterion is winning ribbons in competition then you had better find out what the BJCP has to say about the style. Otherwise you are free. It is entirely possible that you can brew a better Pilsner than they do (or did) in Pilsen because you can do anything you like. In general the trend in commercial brewing is to use water of pretty minimal mineral content but that doesn't mean that you have to do that. It is just another of many avenues you may wish to explore.