Gypsum

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GlentoranMark

GlentoranMark

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I'm going to do a Stout in the next few days but the recipe calls for Gypsum. What exactly is it and what is it used for?

I'm in a soft water area, I'm thinking it's something to do with the water?
 
Gypsum added to burtonise the water. The water in Burton on Trent is very hard, this suits the Burton ale style. You should only add it if you have soft water.

I'm not experienced enough with water treatment to know whether it would make any difference with a stout. The one time I did add it I didn't realise that my water is already quite hard. Gypsum has laxative effects
 
If, like me, you’re in a soft water area, it’s a good idea to add some gypsum (calcium sulphate) and/or calcium chloride to your brewing water. The calcium helps achieve a good mash pH, promotes enzyme (amylase) activity and it’s good for the yeast too. Stouts, depending on the recipe, can be a problem in soft water areas. But there are tricks that can be used.
 
Yes Belfast here, I'm unsure of my water profile although I do know it's pretty clean at around 8-10ppm total dissolved solids (TDS). We don't suffer from limescale although that could be due to a low TDS.

Recipe (to be adjusted for a 21L brew as I'm metric)

5lb Pale Malt, (I'll use Irish Stout Malt)
2lb Flaked Barley
1lb Black Barley
2.25oz EKG (probably use whatever I have in the fridge and adjust)
Irish Moss
Gypsum
5 gallon water (it recommends Dublin water profile as it's a Guinness clone)
Wyeast Labs #1084
 
MyQul said:
Mark, have you checked your water Co.'s website to see if they have a online water report for your area?
Click to expand...

Things have fairly changed since I last done this 10 years ago. It took the water company 4 weeks to get back with information that was of no use to me then. I ha a TDS meter and measured less than 10ppm where I live (which is pretty pure TBH).

This is the info on the website:

Supplying Water Treatment Works Dunore Point
Dishwasher Setting 1-2
NI Hardness Classification Slightly Hard
Clark English Degrees 7.7
French Degrees 11.0
German Degrees 6.6
mg/l CaCO3 109.6
mg/l Calcium 43.9
 
Last edited:
GlentoranMark said:
Things have fairly changed since I last done this 10 years ago. It took the water company 4 weeks to get back with information that was of no use to me then. I ha a TDS meter and measured less than 10ppm where I live (which is pretty pure TBH).

This is the info on the website:

Supplying Water Treatment Works Dunore Point
Dishwasher Setting 1-2
NI Hardness Classification Slightly Hard
Clark English Degrees 7.7
French Degrees 11.0
German Degrees 6.6
mg/l CaCO3 109.6
mg/l Calcium 43.9
Click to expand...


Not much info to go on there, is there . I treat stuff water co.'s put on there websites as just a guide anyway. It's best to either test your own water for things like bicarbonate hardness or pay a company like murphy & son to test your water. The other thing you could do is ask a local microbrewery for the test results from when they (as I imagine most micro/breweries get there water tested) did it.
I've got a murphy & sons report that was commisioned by a micro brewery in bermondsey which is about a mile or two away from me which was passed on to me by another forumite
 
rodabod said:
I reckon the last two lines give you enough info to get the water treatment in the right ballpark. I don't think it's essential, but for a stout like that with soft water, it may make sense.
Click to expand...

I assumed we had soft water because we don't suffer from limescale but that could be due to the water being pretty pure in the first place. Reading that report it says the water is slightly hard.

hard-water-map-uk.gif
 
GlentoranMark said:
Things have fairly changed since I last done this 10 years ago. It took the water company 4 weeks to get back with information that was of no use to me then. I ha a TDS meter and measured less than 10ppm where I live (which is pretty pure TBH).

This is the info on the website:

Supplying Water Treatment Works Dunore Point
Dishwasher Setting 1-2
NI Hardness Classification Slightly Hard
Clark English Degrees 7.7
French Degrees 11.0
German Degrees 6.6
mg/l CaCO3 109.6
mg/l Calcium 43.9
Click to expand...

From what I can see :-

Chloride 22
Nitrate 2
Sodium 15
Sulphate 77

Doesn't give magnesium but it's normally 1/4 of calcium so that puts it around 11.

Your chloride:sulphate ratio is heavily sulphate, off the top of my head I can't remember if that means hoppy or malty.
 
The great thing about us brewers is it's all about experimenting. Try this brew with a teaspoon of gypsum.. try the next without, and the one after, 2 spoonfuls.. As long as you like the taste! You never know.. You may win an award! :thumb:
 
From the meagre information you've been given, one might wonder why you'd want to add gypsum (sulphate) for a stout? You'd probably manage just fine adding nothing to your water!

You might add a touch of sulphite (half a Camden Tablet in 10-20 gallons) to see off any chlorine.
 
Last edited:
Email NI water mate. Tell them you are a homebrewer and are looking for the full water report for your postcode. That's what I did, and I got it back in two days. Also, because I told them specifically what I was looking for, they gave me those results in their introduction so I didn't have to go through the whole report. Excellent service!

MM
 
GlentoranMark said:
Yes Belfast here, I'm unsure of my water profile although I do know it's pretty clean at around 8-10ppm total dissolved solids (TDS). We don't suffer from limescale although that could be due to a low TDS.

Recipe (to be adjusted for a 21L brew as I'm metric)

5lb Pale Malt, (I'll use Irish Stout Malt)
2lb Flaked Barley
1lb Black Barley
2.25oz EKG (probably use whatever I have in the fridge and adjust)
Irish Moss
Gypsum
5 gallon water (it recommends Dublin water profile as it's a Guinness clone)
Wyeast Labs #1084
Click to expand...

For some reason I thought you were brewing in Scotland :oops:

That amount of black malt is going make a nice stout. It might drop the mash pH too much, though, even if your water is slightly hard. You can add precipitated chalk to the mash to bring the pH back up, but you need a means of measuring pH and, TBO, it's a PITA. The best option, IMO, is to cold steep the black malt. This avoids to mash pH problem and leads to a slightly smoother stout.

As far as adding a tsp of calcium (gypsum or calcium chloride) goes, don't assume even in hard water areas there's sufficient calcium (ions) available. Unless you know you have at least 50mg/L in your tap water, add a tsp. There's nothing to lose and everything to gain.

Edit: just read your partial water report. You have 43.9 mg/l calcium. I'd add a tsp of gypsum.
 
I tend to steep highly roasted malts separately at mash temperature, or add them late to the mash, or to the sparge. I like the roast flavour, don't want to damp it down by cold steeping.
 
clibit said:
I tend to steep highly roasted malts separately at mash temperature, or add them late to the mash, or to the sparge. I like the roast flavour, don't want to damp it down by cold steeping.
Click to expand...

I find cold steeping enhances the roastiness of black malt. You still get the acidity and bitterness. It's just a little smoother and allows a hint of dark fruit to come through. But, yes, keeping the black malt separate from the mash is the trick.
 
I'm getting water from the same place Mark, reconditioned Lough water from Dunore Point lol

The last two pages of this pdf are the water analysis for Dunore.
Dunore 2014 Analysis

Sorry just read through it it gives to much info but not enough of what we need.
From another page "Home-brewers may be interested in the Calcium, Magnesium, Carbonate, Sodium,
Sulphate, Chloride and pH levels of their water supply. If you cannot locate the
information you require, please contact us at [email protected] "
 

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