Problems with my first all grain DIPA. What happened?

It sounds like you have a gravity measurement error somewhere.

But just to know where to start looking... What was the volume of wort when you took the reading of 1.055?
What was the volume of wort when you measured 1.061, including whatever wort was tied up in your hops?

 

Sounds about right. So you would have had these total "Points" of gravity in your wort...
9 gallons x 55 points per gallon = 495 points
Now add another 34 points for your 12 ounces of sugar...
495 points plus 34 points = 529 points total

A post boil OG of 1.061 would mean your total post-boil wort volume must have been...
529 Points / 61 Points per Gallon = 8.67 gallons

So 6 gallons into the fermenter, plus .75 gallons in the kettle = 6.75 gallons accounted for...
8.67 gallons total - 6.75 gallons accounted for = 1.92 gallons unaccounted for. That would equate to the absorption for about 2 lbs of leaf hops. Or a lot more pellet hops. I'd be curious about type and amount of boil hops.

Assuming you didn't use that many hops, my guess would be that your first gravity reading (or the corresponding temperature measurement) was off, and that your mash efficiency was somewhat lower than what you were expecting. I suspect this first gravity reading, because it actually involved two significant measurements.

Also, you may have had a little more wort left in the kettle than what you eyeballed to be about 0.75 gallons. This would also explain some missing sugars.

 

On an 8.25 g (preboil) volume, you boil off 2 gallons in 60 minutes? That is 24% per hour and highly unlikely. My guess is that you have either added the 4% cooling shrinkage loss or some hop absorption loss or some of your transfer loss or A COMBO OF THOSE THINGS into that estimate. Your estimate of 2.75 gallons boiled off over 90 minutes is a bit more conservative (20% per hour) but still way too high. That being said, the extra volume you claim to be losing due to boil off (which would boost your gravity) is probably actually being lost in other ways that don't boost your gravity so ultimately that extra liquid contributes to your low gravity. If so, minimizing those losses will allow you to start with a smaller volume which should help increase your gravity.

After all, you are claiming you start with 8.25g preboil, boil 2g off, and somehow get 6g into your fermenter.... That simply isn't possible. Say you did boil 2g off, that leaves you with 6.25g now subtract 4% cooling expansion loss and you are down to 6g. That means you are losing NO VOLUME to hop absorption, kettle dead space, trub, or transfer....

Also, who is crushing your grain? Has it been consistent from batch to batch?


To help you get your numbers down, we'd really need to know things like:

# in the overall grain bill (will help us calculate your mash extraction %)
preboil volume (9 gallons)
preboil gravity (1.055)
postboil volume (before cooling expansion loss)
postboil gravity (1.061)
kettle dead space / trub loss (0.75 gallons)
hop absorption loss (can be ball parked after knowing the postboil volume and amount of kettle hops you added + hop format)
transfer loss (can be ball parked once we know the postboil volume @ flameout)
volume in the fermenter (6 gallons)

 

18# of grain @ 0.13 gallons per pound = 2.34 gallons of wort lost due to grain absorption

that reduces your 8g of strike water (which is actually 1.78 qt per lb thickness btw) down to 5.66 gallons of potential 1st runnings to capture

now if your massive MLT dead space estimate (1.5 gallons) is correct, you only captured 4.16 gallons of 1st runnings
if your estimate of 4.5g of 1st runnings is correct, then your MLT dead space is closer to 1.16 gallons

either way, you are definitely losing sugars in that large amount of preboil wort loss range of 1.16 - 1.5 gallons
but that loss should be the same from batch to batch, so it doesn't really account for why this batch seemed worse

Lets assume your deadspace is 1.16g and you did collect 4.5 gallons of 1st runnings + 4.5g of second runnings

Now you have 9g preboil @ 1.055 SG (76% mash extraction for that grainbill)

If you boil off say 2 gallons over the entire 90 minutes (1.33 gallons per hour), that would reduce you to 7 gallons post boil

Subtract 4% (0.28 gallons) for cooling expansion loss = 6.72 gallons

Now if you collected 6 gallons in your fermenter, that leaves 0.72 gallons to lose btw hop absorption, the trub / wort you left behind in the kettle, and any wort left behind in any transfer hoses you might have.

That puts your brewhouse efficiency at about 61% for this batch with an OG of 1.072

With your actual OG of 1.061, your brewhouse efficiency was only 51%

76% mash extraction being reduced to 51% brewhouse is a huge loss of sugar btw the boil kettle and the fermenter. I doubt this is what actually happened and suspect something is wrong with your mash extraction calculation / preboil gravity reading instead.

You say your preboil gravity reading was 1.039 @ 139F

How exactly did you measure your preboil gravity? With a hydrometer or a refractometer?

If with a hydrometer calibrated at 60F, then yes that would equal a 1.055 preboil OG

If with a refractometer, it might be a refractometer with ATC which means it already adjusted the temperature for you and your actual preboil gravity was indeed 1.039

If that's the case, you would have 54% mash extraction efficiency and 51% brewhouse efficiency. That 3% gap is more likely than the 25% gap previously mentioned above. It also would make more sense that you had a 54% mash extraction than a 76% mash extraction, considering you are losing at least 1.16 gallons of your wort to your mash tun dead space. I don't see how you could possibly achieve a 76% mash extraction with a batch sparge if you are indeed leaving 1.16 gallons of your 10.16 gallons of potentially collectible runnings behind in your MLT. For comparison, I used to hit 79% mash extraction batch sparging myself and I had 0.19 gallons of dead space in my MLT and had a 13.5 gallon preboil volume. So my dead space was 1.4% of my total potentially collectible preboil volume, while yours is 11.42%

With regards to your dry hop question, yeah I'd just stick with the same amount of hops. The lower OG might increase your bitterness a bit but, considering PTE already has an insanely high IBU it won't matter.

 

Deadspace is the volume of wort (in addition to grain absorption) that won't be drained. It doesn't matter how many times you recirculate... you still lose that volume. Now, your mash efficiency might be higher due to recirculation...in that case there is more sugar in your runnings and more sugar left behind in the deadspace.

Anything you can do to reduce wort losses will (all other things being equal) increase your mash and/or brewhouse efficiency.

The more you brew (and take good measurements and notes), the better you'll dial in your system and process. The more you can actually measure (rather than estimate), the better. But estimate what you have to...for example, this beer had a larger grist than your previous batches, but I get the impression you were expecting the same mash efficiency. You can estimate expected changes in efficiency with a little math or a good tool.

 

If the liquid is draining from it, then it's not a deadspace. I talked about deadspaces, because you had identified it as one.

Bigger grists will have lower mash efficiency than smaller grists. You can use something like the Mash Efficiency Predictor in Brewcipher to estimate how the efficiency will change. Or you can do it be feel/experience, but it doesn't sound like you're quite there yet.

I would measure all your equipment/process (true) deadspaces/losses. Also, measure (rather than eyeball) all your volumes.

 

You have a hose on the ball valve outlet, right? The dip tube will get most of the wort out if you have a hose that goes below the bottom of the kettle. If not you can only drain to the ball valve height, and then it breaks the siphon.

I have a similar set up. BTW. Might leave a pint behind.

 

Are you sure your thermometer is calibrated? I lost 15% efficiency when mine was out of whack.