Water Adjustment Suggestions

I recently started brewing(extract) and have 2 batches under my belt.
The problem is both batches came out with a bitter aftertaste, and not hop bitterness either. The bitterness dissipates as the beer reaches room temp.
I used 5 gallons of bottled RO spring water, plus 1 gallon of tap water on both batches. They were both Amber Ales, identical kits from Morebeer.
Full 6 gallon boils.
Could the water I used be the culprit?
If so, what adjustments to my water should I make?
Below is my city's water report
Any suggestions would be greatly appreciated.


Aluminum (mg/L) (2007) <2
Calcium (mgjL) (2007) 21
Sodium (mgjL) (2007) 5
Carbon DiOXide (mQll) (2007) 2.6
pH 6.95
TDS lmgtL) (2007) 256
Total Hardness (mgjL) (2007) 124
Total Alkalinity (mgll) (2007) 103.2
Chloride (mall) (2007) 7.52
Magnesium (2007) 4.82
Color (Unlls) (2007) <5
Sulfate (mg/l) (2007) 41.19

Your sulfate:chloride ratio is rather high, but it's also hard to say what is in your extract. It couldn't hurt to add a couple grams of calcium chloride to get your chloride ion ppms up.

Overall it seems you have pretty good brewing water, so for these suggestions I'm going to give you don't use RO water.. use all tap.

The only solutes you really need to concern yourself with are calcium, magnesium, sodium, chloride, sulfate and alkalinity. If you'll notice, your sulfate concentration is waaay higher than your chloride concentration. That's your problem. You're looking at a Cl:S04 ratio of 0.15, which will result in a very bitter-forward beer. Balanced is 1.0, as you could guess, and above that you get a malty-forward beer.

Add 1.25 grams of calcium chloride if you're making a balanced beer and add 1.75-2.00 grams for maltier beers. Hell, even if you're going to make a bitter beer I'd add 0.75 grams so it won't be astringently bitter.

Thanks a lot guys.
I'm definitely going to give that a try on my next batch.
My boss brewed in the past. I told him my issue, and he asked me how long it has been since I bottled it. I told him 3 weeks. He scoffed, and said put in the closet, forget about it and in 6 months try it. He claims he made a porter that was undrinkable. He thought he'd tossed it out, but a year later found it, and tried a bottle. He said it was amazing!

I'm waiting for my crappy oatmeal stout to get better. It's on month 8 and it still sucks. Be careful with your water adjustments, that beer was a casualty of a bad edit to Palmers RA spreadsheet. When I fixed it, I realized I ended up with over 400 ppms calcium and way over on my other ions too. You can definitely taste it in the beer, harsh, no maltiness at all.