How much Lactic acid ? - Home Brew Forums

Register Now!
Home Brew Forums > Home Brewing Beer > Brew Science > How much Lactic acid ?

Reply
 
Thread Tools
Old 08-04-2009, 01:03 PM   #1
Bru
Recipes 
 
Jul 2009
Johannesburg, South Africa
Posts: 839
Liked 2 Times on 2 Posts



My pH from the tap is 8.05.
How much lactic do I add (per gallon) to get it down to +-6.5 ?
Is the mid sixes the correct pH for sparge water ?
I assume the amount of lactic is dependant on its strength ? How do I get this ?
When I check the pH of the sparge water after adding the lactic how do I adjust the figure to compensate for temperature ?

 
Reply With Quote
Old 08-04-2009, 01:53 PM   #2
rsmith179
 
rsmith179's Avatar
Recipes 
 
Feb 2009
Cleveland, OH
Posts: 934
Liked 1 Times on 1 Posts


Why not just add a pH buffer into your water such as 5.2? That would ensure that your water is almost perfect for homebrewing without too much work. Check out this link:

Austin Homebrew Supply
__________________
"Brewers enjoy working to make beer as much as drinking beer instead of working."
-Harold Rudolph

 
Reply With Quote
Old 08-04-2009, 01:59 PM   #3
Bru
Recipes 
 
Jul 2009
Johannesburg, South Africa
Posts: 839
Liked 2 Times on 2 Posts


Im in South Africa, 5.2 is unfortunately not available.

 
Reply With Quote
Old 08-04-2009, 02:10 PM   #4
Evan!
 
Evan!'s Avatar
Recipes 
 
Aug 2006
Charlottesville, VA
Posts: 11,863
Liked 87 Times on 72 Posts


JP has an excel spreadsheet that you can use to figure it out. It's available for free download somewhere at howtobrew.com...I don't feel like finding the link right now, though. Just look for brewing water, "understanding your pH", etc.
__________________
MOSS HOLLOW BREWING CO.
Aristocratic Ales, Lascivious Lagers


.planned:
•Scottish 80/- •Sweet Stout •Roggenbier
.primary | bright:
98: Moss Hollow Soured '09 72: Oude Kriek 99: B-Weisse 102: Brett'd BDSA 104: Feat of Strength Helles Bock 105: Merkin Brown
.on tap | kegged:
XX: Moss Hollow Springs Sparkling Water 95: Gott Mit Uns German Pils 91b: Brown Willie's Oaked Abbey Ale 103: Merkin Stout
98: Yorkshire Special 100: Maple Porter 89: Cidre Saison 101: Steffiweizen '09 (#3)

 
Reply With Quote
Old 08-04-2009, 02:13 PM   #5
Beerrific
 
Beerrific's Avatar
Recipes 
 
Mar 2007
Georgia
Posts: 5,562
Liked 54 Times on 46 Posts


Unfortunately it is impossible to tell from the pH of your tap water alone. You need to know how much of a buffer capacity you water has to be able to predict how much acid you will need to add to get your water to a certain target.

Ideally you would just add enough acid to "max out" the buffering capacity of the sparge water and use neutral water (pH 7) or you could go a little further towards 6.

Compensating for temperature depends on how you are checking the pH. Some digital meters have built in correction. If you are using strips, I would recommend checking with the manufacturer for that correction.

 
Reply With Quote
Old 08-04-2009, 05:13 PM   #6
Piotr
Recipes 
 
Jun 2008
Poland, EU
Posts: 463
Liked 5 Times on 4 Posts


Quote:
Originally Posted by Beerrific View Post
Unfortunately it is impossible to tell from the pH of your tap water alone. You need to know how much of a buffer capacity you water has to be able to predict how much acid you will need to add to get your water to a certain target.
+1. Sometimes pH drops down like a stone, sometimes barely moves, when you add the acid.

For my water I add 3-5 ml.

 
Reply With Quote
Old 08-04-2009, 05:38 PM   #7
cactusgarrett
Recipes 
 
Apr 2008
Madison, WI
Posts: 975
Liked 7 Times on 5 Posts


Quote:
Originally Posted by rsmith179 View Post
Why not just add a pH buffer into your water such as 5.2? That would ensure that your water is almost perfect for homebrewing without too much work. Check out this link:

Austin Homebrew Supply
Also, just so everyone's on the same page, you actually add the 5.2 stabilizer to the mash, not total brewwater (sparge or top off).
__________________
~~ Malted barley wants to become beer. ~~

 
Reply With Quote
Old 08-05-2009, 05:57 AM   #8
Bru
Recipes 
 
Jul 2009
Johannesburg, South Africa
Posts: 839
Liked 2 Times on 2 Posts


Why pH of 5.2 ? Recommended pH for mash and sparge is higher.
You mention 5.2 is added to the mash not the sparge water - I assume the buffer is strong enough to reduce the pH of the sparge water even after the mash has been drained ?
How many ml of 5.2 does it normally take (Im trying to get an idea of how strong it is).

 
Reply With Quote
Old 08-05-2009, 07:49 AM   #9
Piotr
Recipes 
 
Jun 2008
Poland, EU
Posts: 463
Liked 5 Times on 4 Posts


pH of hot sample is a bit lower than pH of cold one, ~0.3 pH difference (hot 5.2, cold 5.5). Actually, you should cool the sample down to room temperature for pH measurements, to get consistent values.

About sparge water: I add about 2 ml of 50% food grade lactic acid (or 1 ml phosphoric acid) for each 5L of sparge water. For my moderately hard water, it takes pH down to low 5's or high 4's.

 
Reply With Quote
Old 08-05-2009, 12:10 PM   #10
cactusgarrett
Recipes 
 
Apr 2008
Madison, WI
Posts: 975
Liked 7 Times on 5 Posts


Quote:
Originally Posted by Bru View Post
You mention 5.2 is added to the mash not the sparge water - I assume the buffer is strong enough to reduce the pH of the sparge water even after the mash has been drained ?
How many ml of 5.2 does it normally take (Im trying to get an idea of how strong it is).
It isn't as important in batch sparging as it is in fly sparging, but provided your water isn't CRAZY basic, and provided you typically stop sparging at a reasonable point (no lower than 1.012 final runnings), treating sparge water isn't a dire necessity.

pH 5.2 stabilizer is a powder, and it only takes about half a tablespoon per 5gal batch mash. Also, like any buffer, it's only so strong and if you're water is crazy basic it won't work to it's fullest potential. Dilution with DI water is needed then.
__________________
~~ Malted barley wants to become beer. ~~

 
Reply With Quote
Reply
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
When to add Lactic acid? OdinsBrew Beginners Beer Brewing Forum 2 01-13-2009 03:55 PM
where can i get lactic acid Surfman Recipes/Ingredients 2 06-11-2008 10:52 PM
Sour Mash/Lactic Acid instereo13 All Grain & Partial Mash Brewing 15 06-03-2008 01:16 AM
Lactic acid kabert7 Extract Brewing 2 07-26-2007 02:23 PM
Lactic Acid Technique PFlint General Techniques 2 12-09-2005 05:38 PM


Forum Jump