HELP! Ultra high attenuation

WHat % of the grain bill was made up of simple sugars?

 

How do they taste? Sounds a bit like an infection to me

 

Much higher than expected levels of carbonation in the bottles are one sign. Off flavors could be sour or vinegary flavors, yogurty tartness, "funky" flavors, buttery, etc. It would depend on what critters got in there.

 

Mash temp? Batch sparge, fly sparge, no sparge? Is your thermometer calibrated? What was temp at the start of mash and at the end of mash? Mash out or no mash out? If no mash out how long until runnings were on the burner?

 

The only explanation I have is that your runnings continued to become more fermentable as they sat after runoff. If you measured the mash after you added the 168F sparge water, I'll bet it would only be upper 150's temp, so that's continuing to become more fermentable as well. You could mash higher, add a mashout infusion, heat the first runnings immediately, and/or sparge with hot enough water to reach 168F in the mash (probably north of 180F sparge water). Some combination of those will make your beer attenuate less no doubt.

 

150-151 should yield a highly fermentable wort, and without performing a mash-out the enzymes should continue (to an extent...) to do their thing in the kettle.

Like @DarrenE said, try mashing higher, etc.

If you're still getting that kind of attenuation, it could be an infection...

 

I use basically the same mash method. I don't mash out. The first runnings sit in the kettle for about 20 minutes before I light the flame. The FG of the beer is always near what the software predicts.

A low single digit FG with the yeast you used doesn't happen under normal circumstances.

 

something doesn't seem right here…unfortunately not sure we're gonna solve it, but temperature when taking the hydrometer sample is about 65F and you're reading it at eye level? If that is the case…I third with DarrenE's suggestion.

edit: just saw the final sentence of your first paragraph…so discount my suggestion...

 

http://maltingandbrewing.com/beer-bacterial-infection.html

Cheers!

 

An infection doesn't have to be bacteria. You could have a wild yeast infection. The early stages don't necessarily produce obvious off flavors.

 

How did they assure you?

Have you put your hydrometer in a glass of water to see what it reads?

 

Don't look a gift horse in the mouth. Brew big, skip the hops and distill.

 

Not necessarily. Specific gravity is just a measure of the density of a liquid, and in the case of wort, the amount of sugars present. Depending on the source, some sugars are not fermentable (caramelized sugars from caramel malts, for example).

 

I just wanted to clarify that I'm not advocating doing all of these at once. For example if you added a mash out step you definitely wouldn't want to batch sparge with water hotter than 168. I see that CarolusP already answered your gravity question.