Author Topic: Harshness - How much alkalinity is too much?  (Read 13483 times)

Offline The Rabid Brewer

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Re: Harshness - How much alkalinity is too much?
« Reply #75 on: October 05, 2010, 09:34:27 PM »
I can now report that the correlation between RA and SRM that is shown in the How to Brew nomograph is inappropriate

I'd be curious on getting your opinion on the "New and Improved Residual Alkalinity Spreadsheets" that Palmer has posted on his site dated September 2009.

Spreadsheet using U.S. Units
Spreadsheet using Metric Units

In these spreadsheets, the input is SRM and the output is a range of RA. In the instructions he states:
Quote from: Palmer
Darker malts have more natural acidity, and therefore require more residual alkalinity to balance them to arrive at the optimum pH. However, the relationship is a general one – different malts of the same Lovibond color value can have different amounts of acidity. You can use the calculated color of a beer recipe as a guide, but don’t rely on it as gospel to determine the appropriate amount of residual alkalinity; it is a general relationship, like cloud color and rain.

He goes on to say:
Quote from: Palmer
Remember, roastier grain bills will have a higher acidity than grain bills composed of caramel and toasted malts. Look at the range of RA present and choose a number that you feel is appropriate to the style of beer you want to brew.

Right or wrong (feel free to comment) this is the way I've been using the spreadsheet. For a desired SRM, use the spreadsheet to calculate a range of RA. Choose an RA target based on the roast level of the malts, then tweak salt additions to accomplish three things simultaneously:

- Hit the target RA which should help get close to the appropriate mash pH
- Stay within appropriate limits for the important ions
- Target a level for the "flavor ions" (Na, Cl, SO4) based on what flavor profile I'm trying to achieve

Palmer also gives the following guidelines (from How to Brew) for the "brewing range" for each ion:
Quote from: Palmer
Ca = 50-150
Mg = 10-30
HCO3 = 0-50 for pale, base malt only
          = 50-150 for amber-colored, toasted malt beers
          = 150-250 for dark, roasted malt beers
Na = 0-150 (sweetness, round smoothness)
Cl = 0-250 (fullness)
SO4 = 50-150 normally bitter
        = 150-350 very bitter

For my water (Ca/Mg/HCO3/Na/Cl/SO4 ~=  35/16/120/34/21/18) I find that when making a light beer (e.g. SRM=5) I often can't achieve the target RA using salt additions without exceeding the "brewing range". In those cases, I add acidulated malt as a source of lactic acid to drive the pH lower. (The spreadsheet allows one to enter mL of Lactic Acid, and one can calculate the amount of acid malt to use assuming it has 2.5% lactic acid by weight.)

Finally, Palmer also notes that
Quote from: Palmer
"[T]he chloride to sulfate ratio is known to be a strong factor for the taste of the beer. A beer with a ratio of chloride to sulfate of 1-2 will have a maltier balance, while a beer with a chloride to sulfate ratio of 0,5-1 will have a drier, more bitter balance."

Too bad he doesn't provide a reference, but I'm not inclined to dismiss it out of hand, either. For now, I treat it as a interesting data point, but haven't been using it to target RA or salt additions.


« Last Edit: October 05, 2010, 09:37:17 PM by The Rabid Brewer »
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Offline johnf

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Re: Harshness - How much alkalinity is too much?
« Reply #76 on: October 06, 2010, 06:53:38 AM »
The important part of Palmer's spreadsheet instructions, and the part few people follow, is not to rely on the model.

The part I disagree with is that acidity requires alkalinity to balance. Distilled water pH with the palest malt is 5.8. If you want the pH to be, say, 5.4 you need quite a bit of acidity to get there before you worry about adding alkalinity to balance.

In my experience, I've found that I never actually need to add alkalinity and I almost always need to add acid. If I relied on the spreadsheet (which it tells me not to do) rather than checking mash pH with a meter, my pH would normally be much higher than desired.

Offline beersk

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Re: Harshness - How much alkalinity is too much?
« Reply #77 on: December 16, 2010, 09:05:39 AM »
I've wondered about yeast bite in my brews from time to time, I have a hard time getting the yeast to drop out quite often.  What is a good temperature to crash the beer at in order to accomplish this?  I've also considered installing a whole house filter canister with either a coarse filter or a 2 micron filter... haven't tried it yet though.

I'm getting better at making mineral additions so I can brew lighter colored beer but still not quite what I want, my brews are coming out too smooth now imo.  If I crank the Co2 up it generally helps add more crispness.  So I'm still dialing water adjustments in... I tend to do two or three batches over a period of a weekend rather than brewing every few weeks or month so it allows me to judge all of them about the same time. 

Man I know what you mean about your beer being "too smooth".  I have the same thing going on in my brews, and it's not a bad thing, but I want more crispness in my darker beers and a little more bite in my IPA's.  Of course I'm just using straight up Iowa City tap water, which is pretty good water, but I'm pretty sure I need to make some mineral additions to get the water I need for the styles I like to brew (which are mainly IPA's and dark beers).
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