adding gypsum=efficiency issues?

[slanted & enchanted]

i brewed an IPA yesterday, and to try and replicate (well, get closer to) burton on trent water i used around 40 percent bottled water in tandem with my own filtered tap. i then added gypsum to get to this water profile:

Calcium (ppm) 177 Magnesium (ppm) 16 Alkalinity as CaCO3 144 Sodium (ppm) 50 Chloride (ppm) 59 Sulfate (ppm) 338

to get this i had to add 50 grams gypsum. but this was a 30 gallon batch.

so the problem is that my efficiency, which is usually around 82 percent, dropped to around 50.

everyhting else was the same, we actually crushed a little finer than usual, same mash thickness... would the gypsum affect my efficiency this much? i never check pH but according to my prior water reports and palmer's excel spreadsheet, the pH should be perfect.

any thoughts?

i plan on adding a ton of sugar during fermentation to get back up to a respectable gravity. right now it's heading for a 1.048 and 75 ibu's, which seems a bit out of whack to me. i'd prefer it to be at 1.060 or higher with that ibu level.

[dontblake]

What was the mineral profile of the bottled water? Was it distilled or something like Deep Rock or Dasani?
Usually bottled water is just local water that has been purified to get rid of any nasties, but the mineral profile from the source tends to remain. You need to take that into consideration when building water. Now, distilled water is pretty much free from anything and you will have to add something - Ca especially - to get it right.
Anyway, If you had too much Ca (i.e. from Gypsum) your mash pH could have indeed gone too low & thrown off your efficiency.
The sugar idea is good - you might even consider getting some DME and boil it in some water for 10 min or so, then cool it and add to your ferment in place of the sugar so you have some body.

good luck

[BDawg]

Yeah, the DME idea is probably better.
Plain sugar is gonna dry it out and make it appear THINNER. Maybe a cup of malto-dextrin powder might help, too.

[slanted & enchanted]

i think i was using aqua-systems water (probably a local outfit) which is RO. next time i'll be taking pH readings to double check.

i brew pretty big batches, so i initially though adding DME would be the way to go, but after i worked it out in promash it's so EXPENSIVE. so i'm going to add brown sugar to get me up to 1060 or so and then try it out. if i need to i can add malto dextrin back to it for body.

oh well, this will not be a comp beer, but i'll make it drinkable... it smells awesome right now in the fermenter. 3 pounds of hops SHOULD smell great!