EZ Water Calculator questions, targeting oatmeal stout

It's been awhile since I've brewed (long story but I have not brewed since October), so I am a little rusty with the 2.0 version of the water calculator. It had just come out when I made my last batch.

I am brewing an oatmeal stout (49 SRM with a grain bill of)
9.75# Maris Otter
1.75# flaked oats
1# carapils
.75# chocolate malt
.75# victory
.5# roasted barley
.5# Crystal 80L

My water profile is as follows
Ca 56
Mg 26
Na 23
Cl 10
SO4 9
HCO3 302

I plugged the mineral numbers into the spreadsheet. I also filled in total grain at 15; Crystal at 1.5 (accounted for the carapils and the 80L); Entered 1.25 on the roasted (for the roasted and chocolate).

With no salts added, and no dilution of my house water, it shows me with an estimated mash pH of 4.0 and my alkalinity and residual alkalinity at 248/192 respectively.

So a couple of questions:
1. Does that sound right?
2. How do I account for the Victory, flaked oats and base malt on the sheet?
3. What adjustments are recommended?

Here is my quandry for #3. I usually cut my water with distilled to bring down the alkalinity and pH on lighter beers. Not sure what to do with this beer. I could cut the water and/or add Gypsum or CaCl for the alkalinity issue. But that would further drive down the pH, which is already lower than the desired 5.2.

I could also cut with water for alkalinity and add baking soda to the mash only for the alkalinity issue. Then add gypsum or cacl to the kettle to bring my sulfate back up.

But I am a little timid about adding anything other than gypsum or cacl (the only 2 water adjustment salts I've used). My water is so highly alkaline that I am leery of adding anything that will further increase it.

I would appreciate some thoughts

p.s. - I did get a pH meter for Christmas, so I should be able to see where my actual mash lies on brew day vs. the spreadsheet's estimate.

The pH isn't going to come in at 4.0. You do have a lot of dark malt but you also have a ton of alkalinity. My inclination would be to cut in half with RO/DI water and then do a test mash. I'm guessing that would get you around 5.3 - 5.4 but the only way to know is to experiment. As you have a meter you no longer need to grope in the dark. You can see where you actually are. If the test mash pH is too low, dilute less. If it is high, dilute more.

would you recommend any salt additions? If I am coming in at that range, I was thinking about a small amount of gypsum since my water is naturally low in sulfate.

It's odd though. With a 50% dilution and no salts added, the calculator estimates my mash at 4.8. I know there are a lot of variables that it doesn't account for, and even more that I don't know about, but it gives me pause just the same.

Per the chart, with a 50% dilution my alkalinity and residual alkalinity still come in at 124 and 96. Even for a stout with a lot of roasted malts, am I going to notice this in the taste of the final product?

And how do you go about doing a test mash? I am assuming you mash in the same proportions you would for a full mash. But how large is a test mash? a pound total? Less? More? and how far do you have to carry it? Are you OK to just mix everything and hit mash temps and then measure pH? Then just pitch the mash?

You could add a gram of calcium chloride per gallon (about a tsp per 5 gal). Sulfate is pretty much to taste. I don't think of stout as something where I want the hops to be assertive so I don't add any sulfate to stout but if you like the way it works in a stout then by all means add it.

Yes, even cut 1:1 you will have a lot of alkalinity/residual alkalinity and I am counting on the large proportion of colored malts to provide enough acid to convert most of this to carbon dioxide. But the more there is to start, the more residue there will be, even if it is fractional, and the more likely you are to notice bicarbonate flavor. You could use 2 parts RO water with 1 part your water and have the alkalinity at 80 or 3 parts RO water per part tap water for alkalinity of 62. But then I start to worry about all that dark malt. Mash pH might get pulled too low. Of course, a test mash will tell.

The hard part of a test mash is getting a sample of the grist that is uniform. I guess you could blend the grains thoroughly before milling or mix the whole grist thoroughly after milling. You really don't need much at all. A few ounces is plenty. Weigh it out, put it in a beaker, dump in enough water to get the malt/liquor ratio you like to use. Be sure the water is at strike temperature, hold the beaker at strike temperature for a couple of minutes and then draw off a sample for testing, being sure to cool it to room temperature first.

This is a "house stout". I brew it regularly, although my last few attempts have been before I discovered the wonders of tinkering with my water make up.

I say that, only to say that it's not being brewed for a competition and it's not likely to be consumed by people other than me, my dad and a couple of co workers.

That being said, I may skip the test mash and too much more worry about the alkalinity. I'll let my next couple of batches serve as the test. I think I will go with the 1:1 dilution and the gram/gallon of CaCl to start with (I've had pretty good results so far with CaCl since you pointed me in that direction).

From that batch, I will at least have a starting point for pH. Then I can work on the alkalinity through salt addition or water dilution in future batches. I brew this one often enough that I should always have a bottle or 2 from a previous batch to compare the differences.

The last batch was with my water, undiluted and a teaspoon of gypsum. And it still won a lot of friends.

That approach is fine. Your "test mash" is the beer you are brewing. Take good notes. Measure pH a couple of times in the mash, in the kettle pre and post boil and in the finished beer. Adjust dilution the next time you brew based on what you found this time. You will get it dialed in eventually.

Would you suggest the CaCl in the mash and sparge water both? Or just the mash water?

winvarin said:

It's odd though. With a 50% dilution and no salts added, the calculator estimates my mash at 4.8. I know there are a lot of variables that it doesn't account for, and even more that I don't know about, but it gives me pause just the same.

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The important thing to figure out is that the "calculator" isn't calculating anything. It is modeling mash pH using an extremely simple model that relies on a very big assumption (mash pH is a linear function of grist color) that is observably wrong. As the color of the grist increases, the model is going to be increasingly wrong and for grists like this it is useless.

If you don't want to do a test mash just make sure you have some chalk around the house and go get it if you need it after dough-in.

winvarin said:

Would you suggest the CaCl in the mash and sparge water both? Or just the mash water?

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Unless you have special considerations I see no reason to treat mash and sparge water separately. I treat the entire volume of water (mash, sparge, top up, hops sparge) used in a brew the same way. It's just simpler that way.

ajdelange said:

Unless you have special considerations I see no reason to treat mash and sparge water separately. I treat the entire volume of water (mash, sparge, top up, hops sparge) used in a brew the same way. It's just simpler that way.

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When do you usually add your post mash mineral additions? Do you add it to the sparge water, or in the boil kettle? It just occurred to me as I was looking at my recipe for tomorrow, do I lose some of the mineral additions by leaving it behind in the grain during mashing? Would it be better to add my minerals to the kettle after mashing?

I don't add anything to the mash or after the mash. Anything I add (usually nothing but some calcium chloride) gets added to the water (RO). Often I control mineral content solely through blending straight well and RO. The only post mash thing I might consider (and I have never done it) is addition of acid to the kettle for lower kettle pH.

My brewday has been delayed by a few hours. I got up this morning and was going to get started. So I was going to calibrate my meter as my first order of business. Then I read the manufacturer's instructions to soak the probe in 4.01 solution or storage solution for 4-6 hours before calibrating for thr first time. Oops.

My probe is now soaking away while I get my other gear ready, grind my grain, browse the internet, etc.

At any rate. Calibration does not look to be as ominous as it seemed before. Looks pretty quick and straightforward.