Residual Alkalinity vs. HCO3 levels

Many sources will match the bicarbonates in brewing water with the appropriate style of beer that can be brewed with that water. So in the case of a pale ale, you would want bicarbonate levels lower than 50 ppm or in the case of a stout, much higher, perhaps 200ppm. I've listened to waterganza on The Brewing Network and now all that makes perfect sense to me. Where it gets cloudy is when we talk about residual alkalinity. For example, take the water below, which is very close to my actual water. Using the "matching bicarbonates to beer style" example, having bicarbonates near 100ppm makes the water not so hot for a light colored pale ale. But, since my calcium is so low, I add about 6 or 7 grams of gypsum to my water. Now, using the "residual alkalinity" example, the RA is about 0, which makes my water good for a pale ale according to the nomograph John Palmer created. My confusion is this, I added calcium to the water which made the RA just right for my pale ale, but the 100ppm of bicarbonates are still there, which is not so good. What is the correct assumption....
a) Since the RA of my brewing water after adding gypsum is 0, this water is great for a pale ale
b) Since my water has 100ppm of bicarbonates, this water will never be suitable for a pale ale unless it's cut with RO water.

ca = 14ppm
mg = 17ppm
so4 = 6
na = 6
cl - 18
HCO3 = 100

I don't know! But I thought the questions were interesting, and hope to see that somebody responds.

You might want to post this thread in the brew science forum and see if someone there can help. But it's my understanding that you will not rid your water of the bicarbonates just by adding the calcium in whatever form (gypsum or CaCl). The only ways to reduce your bicarbonates I know of are through:

1. Boiling. I believe you can get them precipitate that way.
2. Acid addition
3. My preferred method, cutting high bicarbonate water with RO or distilled, and making up for the minerals you lost with a slightly larger mineral addition.

My bicarbonate is significantly higher than yours (302 ). So I usually do a 2:1 mix of my water with distilled. Then I use a balance of Gypsum and/or CaCl to bring my Calcium to where I want it. If my RA is still too high after that, I will add 1-3% of my grain bill in acidulated malt to bring my mash pH down.

Remember, RA is really only important for your mash as it affects your mash pH. Any bicarbonate remaining in your sparge water will have no affect on starch conversion and sugar extraction. It will affect flavor only.

When I asked why I should care about bicarbonate in my sparge water, a guy on the brew science board by the name of ajdelange once told me to dissolve some bicarbonate in a glass of water and take a sip.

Speaking of aj, he'll probably read my advice and come drop a chemistry bomb on me. I am still in the learning phase myself and am probably seriously misrepresenting some of what he's taught me in the last few weeks.

Some basic rules of thumb I've picked up from him (and my last couple of beers have been better for them):

1. Bicarbonates are bad unless you are counteracting them through acid additions of dark roasted (or adcidulated) grains. Even if you get your RA (and mash pH) down through other means, try to minimize your bicarbonates on pale and lighter beers because the grains used to brew these beers do little or nothing to counteract the alkalinity the impart. The pH of your water, even when using 100% distilled, is still going to be around 7.0. The grains used in lighter beers are not acidic enough to get you to your target mash pH of arount 5.2. High bicarbonate water will only make it harder to hit your target.

2. Calcium is good. CaCl and Gypsum are great sources of it. When using Gypsum, keep an eye on your sulfates, especially for your less bitter beers. Even in bitter beers, try it a couple of different ways. Get your Calcium from CaCl to keep the sulfates low and determine if you like that taste better. Just because a particular bitter style is high in sulfates traditionally, it doesn't mean that you'll make a better beer by racheting up your sulfates ... only a more authentic beer.

3. Take the brewing spreadsheets with a grain of salt (pun intended). While the EZ water spreadsheet (which I use) is a good general help, some of the advice is not to be taken as the gospel truth. Just because your RA tells you that pH will be suitable for a beer of a certain SRM, it doesn't mean that you'll brew a bad beer if you brew outside of that SRM range.

Same goes for chloride to sulfate ratio. It's ultimately all about taste and perception

I am as I said above, still a water chemistry newbie. I have taken the initial steps of cutting down my alkalinity primarily through dilution, keeping my Calcium at or above 50 ppm and keeping an eye on my sulfates. I take the final step of tracking (as close as I can until I get a full blown pH meter) my mash pH through the use of test strips. This at least lets me know if the measures I am taking are getting me in the right ballpark.

There are a lot of people on these boards far more knowledgeable than I about the chemistry. But so far, the above measures have yielded positive results for me.

Thanks for the info, I assumed that RA was important for mash pH but bicarbonates are important for taste. I'll have to find a balance between the two to get the results I'm looking for.