I know several people have posted similar threads but no one seems to have the exact issues I seem to be having. I have just started formulating my own recipes after following several kits and never having issues coming close to the target OG and ABVs. I have been using Beer Calculus @ Hopville to do the math. Both times I have done this, I have ended up with fairly drastically different OGs than expected.
My first attempt was for a quad with a calculated OG around 1.09. I ended up around 1.065 but the beer attenuated more than expected and my target ABV was only off by about 1% in the long run.
This time I made an "Oktoberfest" in which I aimed for an OG around 1.065 (admittedly a little high for the style) for a 5.25 gallon batch but my OG just came in at 1.041 (adjusted for temperature of 70 degrees at time of measurement).
My grain bill is:
4# munich malt
3.5# pilsner 2 row
3.3# Briess Amber LME
.25 # Dark Crystal
I also made a 2 Liter starter with about 6oz of DME in it.
I did the math accounting for 5.25 gallons, I steeped for 30 minutes at exactly 155 degrees, I boiled about 4 gallons (which boiled down to around 3.25) before adding in the yeast starter and extra water, and stirred a decent amount before measuring to try and make sure the high gravity stuff was being measured too. I checked my hydrometer in tap water and got a .990 reading in slightly colder than room temp water.
Some how I am ending up with less than 50% mash efficiency. How is this possible and how can I correct it? Is it worth trying to salvage that potentially extra 1.5% abv by adding some disolved LME or DME?
I really appreciate the help.