« on: December 07, 2010, 11:36:51 AM »
Well, I note that there is something very wrong with the reported ion concentrations since the ions don't balance. I'm pretty sure the bicarbonate concentration is low since the alkalinity suggests that it should be at least 68 ppm. The other thing that was confusing was the reporting of CaCO3 instead of just Ca. It appears that the Ca content is probably around 18 ppm since the hardness is reported around 3.6 grains/gal, which is fairly soft. The Ca content would be about 29 percent of the CaCO3 concentration based on molarity.
These results then balance reasonably well and the corresponding RA calculates at about 55 ppm. This may be marginal for a really pale beer, but OK for amber to brown beers and not too good for black beers.
Phil's report that he ends up with sharp and thin dark beers is just another case in point for my contention that you MUST adjust RA to suit the beer color to produce great beer. With a RA of 55, his water would create pretty low mash pH which sharpens the flavor (acidifies) and pushes the enzymes to create a more attenuable wort. Neither of which adds to a good perception of a beer created that way. There is no need to adjust your brewing water RA if you only want to make passible beer or OK beer. Your choice.
Now, you may recall that Guinness does purposely acidify their stout with sour beer. But you should also recognize that they add this soured beer AFTER fermentation. This avoids the thinning action that would happen if they tried to acheive their preferred finished beer pH by adjusting their mash and wort pH lower.
Back to Phil's question. He should be adding alkalinity to only the mash water to properly buffer the mash pH. I calculate that he would be adding about 0.4 grams of chalk per gallon of mash water or he could add about 0.3 grams of chalk and 0.1 grams of baking soda per gallon of mash water. That will bring the RA into the 130 ppm range, which is about the minimum I recommend for black beers. I recommend that the chalk addition be limited to less than 0.6 grams per gallon of mash water if he finds that he still doesn't like the acidity and body of beers brewed with the previous amounts. Phil still needs to acidify his sparge water to bring the pH down around 5.7 to 6 and avoid tannin extraction. Don't add chalk or baking soda to sparge water. That amount of lactic acid to achieve the pH goal is about 0.3 mL per gallon of sparge water and he should be doing this for all his beers.
There have been several discussions about how some spreadsheets or nomographs guide brewers to overdo their water chemistry and make soda-water tasting beers. Its unfortunate that one source has spawned this flawed guide that has now been taken up by several of the water spreadsheets out there. But, that is not to say that the approach to pairing mash water RA to beer color shouldn't be used. It only needs refinement. My research of the waters from historical brewing centers and waters around the world has led me to recommend that the proper relationship between beer color and RA is approximately RA = SRM times 4.5. My research also indicates that none of those historical brewing waters (especially the ones known for brewing great dark beers) have RA values greater than 180 ppm. Therefore, my recommendation has been that RA should generally range from 0 to 180 ppm, but I'd say that it could be fudged to about -25 to 200 ppm without ill effect.
Overall, Phil's water is a pretty good starting point for many beers and he only needs minor acid addition to brew pale beer and minor minerals to brew darker.