My gravity is way off (full boil though)

[KepowOb]

So my latest brew is 17 points too high! It's an extract brew, but I did a full boil (started with 6.5, ended with 5.25ish in my carboy, no top off water at all).

I had my recipe in Beersmith, and it estimated my OG to be 1.056. When I measured it, it was 1.073.

Recipe was 7lbs of DME (everything boiled for 60min) and 2lbs of Crystal 60, which I steeped at 155-160F for 40minutes in about 3 quarts of water, plus the hop additions.

I've since tested my hydrometer in distilled water, it read exactly 1.000. Temperature of the wort was 74F when I measured it, and I'm taking into account the temp correction.

Any ideas? I know extract brews can throw off OGs if not mixed properly, but I was under the impression that was only from partial boils and then adding water in afterwards. I've always been within .001 of my OG before this brew, so I have no idea what the heck I did wrong. I'm also sure I didn't put in an extra 2lbs of DME.

I brewed this over the weekend, but I've been going over (and over) everything to see where I might have gone wrong, and I can't figure it out... so it's up to you guys now.

 

[jro238]

Are you sure beer smith took into account that 1.25 gal of boil off? That sounds like it could cause pretty close to the gravity difference.

 

[KepowOb]

Yeah, I have my equipment profile set up properly. Beersmith had me starting with 6.47 gallons and boiling down to 5.5. I had slightly less (say 5.3-5.4... my measurements are by .25gallon increments, and it was just below 5.5), of which slightly more than 5.25 ended up in the fermentor (left a very little bit of gunk and whatnot in the kettle). Maybe I boiled off a bit extra, but not enough to cause that big of a miss.

 

[billl]

Well, you can't create sugar out of nothing, so lets look at the numbers.

DME is around 43 points, depending on the batch. The crystal steep should be about 25 points/lb

So, 43x7+25x2=351 points of sugar. In 5.25 gallons, that would be 1.067. In 5 gallons, that would be 1.070. You might get a little higher out of the crystal, but only a point.

Are you sure you are correcting the temp in the right direction?

 

[KepowOb]

I didn't think I'd be getting anything out of the Crystal without mashing it with some base grains... or if I did, I thought it was be very little (much less than 25 points/lb anyway). If that's the case... then that might just be the answer.

I used an online calculator to correct for temperature. It's also possible I had a little bit more DME. I had two 3-pound bags plus an extra pound I measured out myself... I didn't think of measuring them, but since starting the thread I measured others that I have from the same supplier and they're each a little bit high (not enough for 17 points obviously, but maybe enough to knock it up by a little).