Messages

136

All Grain Brewing / Re: Harshness - How much alkalinity is too much?

« on: August 25, 2010, 10:33:14 am »

Would you guys make this addition for the pH shift or leave the pH at 5.0 and just be done?

I would make the adjustment if, while in the process of doing the mash, I had taken a pH reading of 5.0 - Kai's spreadsheet can provide an estimate to get you close to the actual pH of the mash - what the spreadsheet calculates isn't always exact. This is especially true of dark beers.

If you want an exact answer to your question and you have a pH meter or colorpHast strips (less reliable) do a test mash and take a pH reading and then make the decision.

Based on the information you have currently made available I would not make any additions. RA values North of 150ppm as CaCO3 are rarely necessary to adjust pH.

If you provide your starting water profile I may be able to give you a different answer based on my experience, but I probably wouldn't end up changing my answer. Just my $0.02.

137

Other Fermentables / Mead and Potassium Hydroxide (KOH)

« on: August 25, 2010, 10:04:43 am »

I just had a few questions regarding the use of Potassium Hydroxide (KOH) in mead. I've seen this suggested in multiple sources:

http://www.bjcp.org/mead/Mead_Study.pdf
http://www.ahaconference.org/presentations/2008/KrisEngland_NHC.pdf

Really these questions are more requests for confirmation that I'm going about things correctly and that I'm not a total boob.

In any event - what is a reputable source of KOH? I tried ordering 500 g flakes from Cynmar and they informed me that they don't sell chemicals to individuals. Since then I've located this source which is food grade and it's about 4x as much as Cynmar was selling for the exact same price:

http://www.amazon.com/Grade-Devil-Potash-Potassium-Hydroxide/dp/B0039CIQTI/ref=pd_sbs_auto_2

I did notice in that picture on Amazon that it says 'minimum 90% KOH' on the bottle - which begs the question, what's the rest and is it OK to add this?

Also a quick question about using the stuff if/when I get it. It's been a while since chemistry - since the molecular weight of KOH is 56.1056g/Mol, to get a 2M solution I would add 112.211g to a container and then add distilled water until the total volume reaches 1 Liter and the subsequent solution is KOH at a concentration of 2M, correct?

If that is correct, does this method scale in a liner way (i.e. if I mixed a 500mL solution with 56.1056g of KOH would that also have a molarity of 2? Or 28.0528g in a 250mL solution?).

After I get a 2M solution of KOH can I just add 10mL of directly to my fermenter or is there an intermediary step?

Thanks in advance for the responses.

138

All Grain Brewing / Re: Does more Ca in the mash = better conversion?

« on: August 22, 2010, 09:42:45 am »

Fix, Principles of Brewing Science, 1999, pg 5

Calcium ions also tend to afford thermal protection for mash enzymes (Comrie, 1967). IN addition, they continue to interact with malt phosphate during wort boiling, and the ongoing reaction between calcium and phosphate is the primary reason that the pH decreases in the kettle boil. Calcium ions also tend to inhibit color formation during the boil and facilitate protein coagulation. Finally, calcium ions also influence beer fermentation. For example, they favorably affect yeast flocculation and beer clarification during maturation (Harrison et al., 1963; Saltukoglu and Slaughter, 1983; Taylor, 1990)

He goes on to say (on page 6):

A widely accepted rule in brewing is to have calcium concentrations of at least 50mg/L, and values in the range of 100-150 mg/L are very common.

Anecdotally, I've done mashes with water around 20 mg/L Ca++ and achieved 85% efficiency and I've fermented meads with 0 mg/L Ca++ that have achieved final gravities putting them into the dry range from an initial gravity north of 1.100.
 
However, when it comes to brewing, if you're going to take 4-8 hours of your day to make beer and George Fix and other sources of contemporary beery wisdom have accepted as an axiom that 50 mg/L Ca++ is desirable why not just aim for that as a minimum? Seriously, I'm asking - is there any reason compelling reason, other than anecdotal evidence, that suggests the best beer is made with Calcium concentrations below 50 mg/L or above 150 mg/L?

139

All Grain Brewing / Re: Harshness - How much alkalinity is too much?

« on: August 22, 2010, 12:52:48 am »

RA = SRM x 4.5 

This provides an appropriate ballpark target RA for brewing water.

This is ridiculous for so many reasons. First, the relationship between SRM, RA and mash pH is tenous at best. That is to say there is correlation here but most brewing water spreadsheet draw very strong conclusions from this weak correlation. The net effect being that the entire homebrewing community suffers. If Gordon Strong doesn't want want anything in style guidelines about the relationship between RA and beer SRM it's because he's had to taste too many of the salty "Alka Selzer" beers that result from the jump of logic.
Some reading that is worth while about the subject of RA, Color and mash pH:

http://ajdel.wetnewf.org:81/Brewing_articles/BT_Alkalinity_II/AlkalinityPtII.pdf
http://braukaiser.com/wiki/index.php?title=Beer_color,_alkalinity_and_mash_pH

Second, while I agree that many contemporary sources for RA and subsequent water adjustments are flawed those sources were created by many individuals who have devoted a great deal of time an effort into this work - oversimplifying their work into this equation doesn't serve any purpose except to mislead those people who are ignorant about water chemistry and RA.

One quick example to prove my point. I have a RIS that has a calculated SRM (Morey) of 67. According to your formula that would require a RA of 301.5. In order to achieve this RA (ppm as CaCO3) in my water (which represents a best case scenario since my water has 0 hardness from Ca++ or Mg++) I would have to add 1312ppm CaCO3 which is close to 50g of Chalk in 10gallons of treated water. I brew my Black IPA with water that has a RA of 0 and the mash pH on the last batch was 5.5 - which is on the high end for me. I have no doubt that following this "formula" and using the RA value of 153 and subsequently adding 24 grams of Chalk to my water would have not only put my mash pH out of range it would have made my beer taste like hop-flavored tums.

If people are really concerned with mash pH they have to drop $80 and get a pH meter. If you're concerned with hitting the mash pH correctly every time then you ought to be doing a test mash before your brew day and scaling up your findings (which I don't do because my mash pH needs no adjustment 90% of the time). I'm going to say the one thing everyone hates to see in a forum discussion about water - the vast majority of water needs no adjustment. Brewers that suspect problems with their water are most often misidentifying another problem in their process. Sanitation and fermentation before water adjustment - always! If you want to tinker then build a yeast library not a salt library. I adjust my water to acheive 50 mg/L Ca++ with, typically, equal parts Calcium Chloride and Gypsum. Speaking of which...

The other result from the EZ Water spreadsheet that is flawed is the chloride to sulfate ratio recommendation.  I have never seen this ratio used previously, but I can state that it is not based on any texts or journals that I have reviewed.  It is not a proper indicator of the brewing water promoting a malty or bitter character.

Handbook of Brewing [Ed. Fergus Priest and Graham Stewart] p. 111 - "It appears that, in many cases, it is the relative ratio of the two ions that has the major flavor influence, often irrespective of the accompanying cations."

(note that I haven't read that text either - AJ Delange has, and was kind enough to post this citation here: http://www.thebrewingnetwork.com/forum/viewtopic.php?f=2&t=21450&start=0)

The balance is calculated from the millliequivalents of the major cations and anions in the water.  The milliequivalient value for each ion is calculated from the concentration of each ion , the ion's molecular weight and its ionic charge.  The cations and anions should roughly balance if the water report is correct.

This is the problem with trying to achieve many regional water specifications found around the internet - they are not physically realizable because the the me/L of cations and anions don't balance - like at all...but they don't on my most recent Ward Labs report either so whatever...

End Rant.