Negitive Residual Alkalinity

[churdbird]

I'm new to using Ez-water spreadsheet. My last two batches keep showing a negative r/a? I can assume that this isn't normal? And is it really a problem that I need to worry about? Negative effects?

 

[stpug]

Actually it IS normal to see residual alkalinity at or below zero, however we'll have to wait for one of the water experts to tell us why. All I know is that you are generally aiming for your residual alkalinity to be <20s, and close to zero (either way) is great.

 

[ajdelange]

Residual alkalinity is defined as

RA = alkalinity - ([Ca++] + [Mg++]/2)/3.5

[Ca++] and [Mg++] are the concentrations of calcium ions and magnesium ions, respectively, in the same units as alkalinity (i.e. ppm as CaCO3 or mEq/L) and the RA is then in those same units.

Obviously, if the alkalinity is negative (which it is if you add acid to the water) or if the alkalinity is low or 0 (DI water) and the calcium or magnesium high you will have negative RA. The latter is the case with some Burton waters. There is that much bicarbonate (alkalinity) but there is a ton of calcium from gypsum. These waters have RA's varying from minus a few ppm to -60 or more ppm as CaCO3. This is why IPA is possible without acid addition.

 

[ajdelange]

Residual alkalinity is defined as

RA = alkalinity - ([Ca++] + [Mg++]/2)/3.5

[Ca++] and [Mg++] are the concentrations of calcium ions and magnesium ions, respectively, in the same units as alkalinity (i.e. ppm as CaCO3 or mEq/L) and the RA is then in those same units.

Obviously, if the alkalinity is negative (which it is if you add acid to the water) or if the alkalinity is low or 0 (DI water) and the calcium or magnesium high you will have negative RA. The latter is the case with some Burton waters. There is that much bicarbonate (alkalinity) but there is a ton of calcium from gypsum. These waters have RA's varying from minus a few ppm to -60 or more ppm as CaCO3. This is why IPA is possible without acid addition.

 

[churdbird]

Ok. But w/ an American Wheat. 4# 2 row and 4# wheat malt using R.O. Water gave me a -358.. It far cry from 0 +.. Just playing with the numbers.

 

[ajdelange]

You are obviously not entering the data correctly.

 

[churdbird]

Well I'll double check.

Still shows negative.

Ca. 2
Mg. 0
Na. 5
Cl 3
SO4 6 (2x 3 Labs report)
HCO3. 0

3 gal mash
5 sparge
4# ea 2 row and wheat

Adjustments:
3g Gypsum
2G CaCL2
2g Epsom
All 3 - adjust w/ sparge
2.5ml lactic


R/A -346
Ph 5.5

Did I enter something wrong?

 

[mabrungard]

A beer with very little crystal or roast malt will require a negative RA in order to produce a proper mash pH. For instance, 100% pale malt mashed with distilled water will produce a mash pH in the range of 5.7 to 5.8. The RA for distilled water is 0. Acid is needed to drop that distilled mash pH and therefore, the RA is also negative.

 

[GotPushrods]

You probably have the mash size set about 3x too low. Did you put in 3 gallons for mash volume? 1 gallon might give you those results, as it seems you're probably shooting for R/A of about -100. I think EZ might take your acid additions into account too, so this seems correct.

 

[ajdelange]

In adding 2.5 mL 88% lactic to 3 gallons you'd be adding 2.6 mVal which, added to water with no alkalinity, would render its alkalinity -2.6 mVal or -130 ppm as CaCO3. The calcium and magnesium additions will lower it more but not as far as -346.

 

[jbaysurfer]

I don't know why you're getting such a high (negative/low) number for RA, but try adding some Baking Soda to your mash water (not sparge water, and on the spreadsheet only) and see what that does to the rest of your numbers. Also, are you using acidulated malt? Tweak that in the spreadsheet as well and see if you can get a profile more tolerable.

Edit: this thread is jumpin'. My response is already obsolete. As long as mabrungard and AJ are helping you, ignore me. I've had this problem as well and adding a bit of baking soda to my mash corrected it, but these guys will give you way better info then me.

For AJ/Mabrungard: Is there a negative impact of having too low of an RA (presuming your ph numbers are correct)?

 

[churdbird]

You probably have the mash size set about 3x too low. Did you put in 3 gallons for mash volume? 1 gallon might give you those results, as it seems you're probably shooting for R/A of about -100. I think EZ might take your acid additions into account too, so this seems correct.

I did. 3 gal for mash and 5 for sparge.

 

[churdbird]

Try it in the spreadsheet. Above is all the inputs that I made. Maybe my spreadsheets whacked?