Missed OG with extract beer?

[tri_clamp_ninja]

I want to start this off by saying that I feel really stupid for having to post this. I have been a professional brewer for 6 years and jumped straight into all grain professional brewing before I ever homebrewed one time. I have no problem producing awesome all grain beers, nailing my numbers, and consistently replicating recipes on a commercial scale.

Now, for fun I recently started playing with extract beers on a small scale 5 gal homebrew style set up (extract only and extract + steeping grains) because after doing a 12+ hour double brew shift at work the last thing I want to do is spend 4-6 hours doing all grain beer at home on my days off. Here is where my problem comes in, I keep missing my OG with these extract beers and it's becoming really frustrating. I'll give recipe examples below but i'm using beersmith, the equipment and ingredient profiles have all been modified to match as close to exact specs as I can get, and I'm using a propane burner which I feel may have something to do with it however (as you'll see below) some of these recipes have all the DME added at flame out so it shouldn't be an issue of poor boil not condensing sugars.

One thing I'm unsure of (and it's such an amateur question!) is should my DME weight be based off of preboil or post boil volume? Meaning: say I'm shooting for 1.040 OG, should I base my calculation off of the 5 gal batch size into FV or base it off of a 7+ gal preboil volume? If it helps, i'm doing most if not all of my DME as a flame out addition, I do full boils with no top up water, I am using a very expensive lab/commercial grade Hydrometer and verified the temperature of the gravity sample with a lab/commercial grade thermometer both to have the most accurate reading.

Here are some recipe examples from my beersmith entries:

All Extract Blonde Ale
5 gal batch volume, 7.21 gal pre boil volume, 60 min boil
10 gal stainless kettle, propane burner
-1lb Briess Golden Light DME @ ramp up
-Hop additions @ 60mins + Flame Out
-Nutrient + Whirlfloc addition @ 10 mins
-4lb Briess Golden Light DME @ Flame out
Est OG: 1.044 (per beersmith)
Act OG: 1.037

Here's another example, this time using steeping grains:

Extract + Steeping grain IPA
5 gal batch volume, 7.21 gal pre boil volume, 60 min boil
10 gal stainless kettle, propane burner
-1/2lb Honey Malt
-1/4lb C60
-1/4lb C90
-1/8lb Black Malt
Steeped in 1 gal @ 158f for 20 mins.
After steep, removed grain bag and let drain into kettle before adding water to reach full 7.21 gal pre boil volume.
-Hop additions @ 60, 45, 30, 15, and flame out
-Nutrient + Whirlfloc addition @ 10 mins
-4lb Briess Golden Light DME @ Flame Out
-1.88lb Briess Pilsen Light DME @ Flame Out
Est OG: 1.053 (per Beersmith)
Act OG: 1.047

sooo.....what is happening here?

 

[Yooper]

How are you measuring the volume into the fermenter? If you have, say, a quart of extra liquid going into the fermenter instead of exactly 5 gallons and a quart of trub that you discard, that could easily explain it.

 

[tri_clamp_ninja]

Thank you for your prompt response @Yooper

I have exactly 5 gallons going into the FV based off of a marker I made on the carboy verified by a flow gauge. At most I may be a few fl oz over if I look away. Regardless, my grav reading is taken from a kettle sample not out of the FV so realistically it shouldn't matter if I have 1,3, or 5 gal in my FV as it's all coming from the same wort. Now I can say that I typically have roughly .5 gal of trub left in the kettle (ranges depending on the beer and kettle additions, sometimes it's more with big ipa's). Based off of quick math in relation to my larger commercial equipment that does seem like it's a little high in terms of percentage of total post-boil volume. That 7.21 gal pre boil volume is honestly me taking beersmith as gospel however I've had to do a ton of manual calculations and overrides to beersmith in the past so I wouldn't be surprised if that has something to do with it. Figure: round down that preboil volume to say 7 gal flat and it should (in theory) reduce my post boil volume by roughly the same which then puts my trub at a more reasonable volume and as a hole should help me hit OG due to less water.

Thoughts?

 

[Yooper]

Tossing out .5 gallon of trub is fine- BUT that is why your OG is lower. If you want to compensate for that loss, adding a bit more extract to your recipe and targeting a 5.5 gallon batch would fix it.

 

[tri_clamp_ninja]

Great, thanks! I'll give that a shot

 

[Drewed]

You are boiling off 2.12 gallons in an hour? That’s a mighty powerful burner. This is based off of my limited brewing knowledge, and I’m boiling my wart on a stove, but I don’t loose nearly that much liquid during a boil. However, because of limited pot size, I’m only starting with about 3 gallons in the pot, boiling hops and a some of the DME/ LME, adding the rest of the extract at flame out, cooling, dumping into fermenter, then topping to 4.5 gallons. At that point I check gravity and add more water if needed (it has always been needed.)