I've always read that bicarbonates between 10-50 pale,
50-100 amber, 100-200 dark.
The color of the beer has little (but not nothing) to do with it. Some rather dark beers (for example, Bock) come out very nicely when brewed with liquor of low alkalinity. The alkalinity required, if any, should be just enough to balance the acidity of the dark malts you use at the desired mash pH. The last Bock I did, for example, used 22.5% Pils, 28% Viennam 38.6% Munich I, 7% Munich II, and a fraction of a percent each Special B and Caravienne. It measured 25.8 SRM and required 1% Sauermalz equivalent in RO water (by which I mean the water was not RO and had appreciable alkalinity so that the grist actually contained 5% sauermalz) for mash pH of 5.4
Your calcium brings that down...
But not by much. The fairly appreciable calcium hardness in this example beer of about 130 ppm as CaCO3 only lowered pH by at most 0.02.
and whatever is left over is your RA and that's what we try to bring down with acid or salt additions to hit the proper ph.
RA is for comparing water. Beyond that you are not concerned with it. You are concerned with the proton deficits of each mash component including water. RA relates to that but worry about mash pH, not RA.
Does that also reflect the over all flavor? Say I brew a something with ale very low SRM around 2-3.
Mash is typically at pH 5.4 or so at which pH 90% of the bicarbonate has converted to CO2 gas and been driven off by the heat. Kettle pH should be at about 5.2 where 93% of the carbo is carbonic acid (which leaves solution). In the fermenter the yeast quickly drop the pH to under 5, say 4.6 where only 1.8% of the carbo is bicarbonate. Then the yeast saturate the beer with CO2. At atmospheric pressure (i.e. while still in the fermenter) the beer will have about 0.2% w/w CO2 dissolved in it which means at a litre will contain about 2000 grams of which 1.7% equal to 34 mg will convert to bicarbonate. Carbonated to a couple of volumes that level will double to 68 mg/L bicarbonate. In summary,
the bicarbonate in fermenting or finished beer attributable to CO2 is much greater than the bicarbonate which has survived mashing and boiling.
Kne with water bicarbonates at 100ppm and another at 50ppm, same calcium, chloride, and sulfate.
???
I add acid to the higher bicarbonate and get them at the same ph through out the whole process. Would the one with a lower bicarbonate let the malty flavors shine over the higher one?
Bicarbonate in mash or mashing liquor is responsible for most of the proton deficit of mash water and therefore water of low alkalinity is generally to be preferred in brewing. If the water has a large proton deficit it must be balanced by things which have proton surfeits such as dark malts and acids. There are consequences in the use of either. If acids are used 1 mEq of the anion of the acid remains behind for each mEq of deficit neutralized. For example, water of alkalinity 100 ppm as CaCO3 (2mEq/L) to be used in a beer to be mashed at pH 5.4 will require about 1.8 mEq/L of acid and will leave behind 1.8 mEq/L sulfate or chloride of lactate or biphosphate ion depending on the acid used. If dark malts are used then the more alkalinty that needs to be neutralized the more dark malt needs to be used and the more dark malt flavors will remain in the beer. Now, of course, that may be desirable and it may be desirable to have chloride and/or sulfate in the beer. Where this is the case it is easier to use RO water and add the chloride or sulfate salt rather than to add bicarbonate and then neutralize it with the acid. At least you don't have to handle strong acids.
You should seldom have to add bicarbonate to brewing water and when you do you should do it judiciously.
