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Old 03-08-2008, 06:39 PM   #1
rocketman768's Avatar
Feb 2008
Evanston, IL
Posts: 1,083
Liked 25 Times on 22 Posts

I am getting ready to try my first partial mash on a marzen/oktoberfest ale according to the recipe below, but I have a few questions about the water I am going to use for mashing.

First, I do not trust my tap water at all and I will be using Deer Park spring water bought at the grocery store. Its water profile is here. For the marzen, I assume I want a residual alkalinity mash pH of 5.7-5.8 since that's what the waters of Munich give. However, the values given on that page have a really wide range, and those give mash pHs of about 5.8-5.9.

So, first question is: is using this water a good idea for this recipe? Second is: should I just use the average values of calcium, magnesium, and bicarbonate levels when calculating residual alkalinity mash pH? Third: do I need more than one rest at 150-158F with the grains I am using?

Thank you!

Final Volume - 5 gal
Boil Volume - 2.5 gal
Boil Gravity - 1.056

---Added Near Flameout---
5.0lb Light DME (Grav: 0.045, Color: 4.5L)
---Partial Mash---
0.4lb Crystal 80L (Grav:0.025 , Color: 80L)
1.0lb Munich (Grav:0.026, Color: 10L)
0.5lb 2-row Lager Malt (Grav: 0.028, Color: 1.5L)

28g Hallertauer (or Liberty) pellets (4% AA) -40min (11.35 IBUs)
28g Hallertauer (or Liberty) pellets (4% AA) -30min ( 9.94 IBUs)

Original Gravity = 1 + 0.045 * 5/5 + 0.025 * 0.5/5 + 0.026 * 1/5 + 0.028 * 0.5/5
= 1.0555

Boil Gravity = 1 + 0.045 * 2/2.5 + 0.025 * 0.4/2.5 + 0.026 * 1/2.5 + 0.028 * 0.5/2.5
= 1.056

Color = 4.5 * 5/5 + 80*0.4/5 + 10*1/5 + 1.5*0.5/5
= 13.05 SRM

Bitterness = 11.35 + 9.94
= 21.29 IBUs

The boil will be the liquid extracted from mashing the specialty grains plus 2 pounds of the DME.

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Old 03-09-2008, 05:49 PM   #2
Poindexter's Avatar
Oct 2007
interior Alaska
Posts: 1,195
Liked 5 Times on 5 Posts

I didn't even follow the DeerPark link. I am not sophisticated enough to talk about water chemistry, so that's out of the way.

I brew with grocery store water anytime my tap water tastes funny. I have used several different brands. What I use is water treated with Reverse Osmosis (RO) and some other technologies, with some trace minerals added back in for taste.

To each 2.5 gallons of water I add a scant 1/4 teaspoon of gypsum. Every beer I have made this way has been tasty enough that I can't possibly blame any minor flaws on the water.

A scant whatever spoon is a little bit less than a level one and a lot less than a heaping one.

Beware distilled water with no minerals in it. I use that stuff to rinse trace minerals off my car when I am getting ready to wax, but don't brew with it. Both the grain enzymes and the yeast need some trace minerals around.

Also beware bottled "spring water". Probably safe to brew with if it is a national brand - but taste a small bottle and look of the chem profile before you commit.

-just another n00b

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