Missed OG by 30, Yikes!

[Supabrew]

I was shooting for an OG of 1.093 for a Dogfish 90-min IPA clone. I used BeerSmith to scale the recipe down from 5 gallons to 2.5. I ended up with a reading of 1.062.

I've been brewing AG for 13 years and never seen such a huge discrepancy.

The thing is that I decanted and added a 0.7L yeast starter and oxygenated the beer before taking the OG reading (with both a calibrated hydrometer and a refractometer) and am wondering how in the world I could have missed it by such a huge number. This is not a normal practice for me, I just forgot to take the reading before moving to the fermenter. Sure, there would be some alcohol from the yeast starter... but I did decant most of the liquid before pitching. Did this have anything to do with the whiff here?

Will you guys weigh in? I am not sure if/how I didn't get incomplete conversion somehow or what and would like your thoughts so I don't repeat a mistake in a future batch.

• 3.78 gallons mash (RO corrected to Pale Ale profile in bru'n water)
• 0.88 gallons sparge (same as above)
• 8lbs 0.2 oz Great Wester Domestic 2-Row (2 SRM)
• 13.2 oz Munich Malt (9 SRM)
• 2.0 oz rice hulls
• Hops (Amarillo, Simcoe, Warrior) continuously added every 5 minutes during boil
• Dough-in at 150, mash for 60 min
• Mash-out at 168, sparge at 168
• Boil for 90 min

The brew will probably still turn out alright (BeerSmith predicted an OG of 1.093 and FG of 1.019 (9.8% ABV). I am hoping that with a lower OG, I will get a lower FG and still make over 7%.

 

[wilserbrewer]

What were your actual volumes? Pre and Post boil volume?
Volume to fermenter?

Did you leave much behind in the brew kettle?

Producing too much wort, and Leaving wort in the kettle can have drastic effects, especially in small batches.

Doesn’t sound like enough grain to get to 1.093, just a guess.

 

[Supabrew]

What were your actual volumes? Post boil volume?

Hmm, now that the foam has settled from the oxygenation, I can see that I ended up with 2.75 gallons in the fermenter. I was using 2.6 gallons as my goal post-boil, knowing that the fermenter is going to eat about 0.53 gallons. Perhaps the extra 0.15 of a gallon threw off the numbers?

There was some wort left in the brew pot. I brewed the batch today in a Grainfather and the pump usually does not get the last 1/2 pint or so, although what was left looked undesirable (trub/hop sludge that crept through the hop spider).

Perhaps less boiled-off than BeerSmith anticipated, though I am using the Grainfather profile for my equipment. Maybe the ambient temp or humidity had something to do with it?

I do not usually brew such small batches, but the lady doesn't like IPAs so I thought I would treat myself to a little keg mid-summer.

 

[Supabrew]

Just pulled the IPA out of the secondary and kegged the 2.5 gallons. It smells heavenly: orange, lemon and a lilly-like floral aroma. Tastes pretty great for being warm and un-carbonated to boot!

The FG clocked in a 1.007 which nets a 7.3% ABV brew. I am going to carbonate it around 10 PSI at 38F using a carb stone then bring it to a get-together next weekend. I don't expect it to last that long!

Thanks again to those who replied about small batches magnifying any miscalculations [natural or man-made ]. Incidentally, I updated my equipment profile based on posts on HBT forums and believe it to be much more accurate now. Time will tell. And by time, I mean tomorrow when I brew a RIS for the fall/winter!