stumped... extract OG

[zorak1066]

I do the math ... for a 3 gallon batch with the malt I added and steeping grains I should be hitting 1.05.
I do the boil for an hour of 3 gals.. top to 3 gals...
hit 10 brix. 1.04.
ive done the math every which way but in Chinese and backwards... plugged and chugged on various recipe calculators
and they all say I should have hit 1.05 not 1.04.
even if I had a tepid boil... the potential gravity of the wort should be the same because the amount of malt is not changing
and its volume at end gets topped to the same level.

I am stumped. could it be that my refractor is a piece of crap?

[BigPapaG]

Questions that come to mind:

Did you stir well before sampling to ensure there was no stratificatin (heavy wort concentratin on the bottom, watery top...

Also, are you adjusting for temp with the sample, or letting it cool or using an auto temp compensating refractometer?

Are you sure you had the right weight of extract? (Check scale if using bulk or in some way measuring it in)

[zorak1066]

stir before sampling: no
temp - the refractometer uses a thin swipe of a sample. it should have been room temp by the time the cover glass went on, which is close to the temp the meter was graded at.
scale and weight checks out.

I did a test. specific grav of a juicy juice type bevvie with hydrometer : 1.06 same sample with refractometer 1.058 so it's close.

at this point all I can think of is a) northern brewer is not packaging lme that is 36 pts per pound per gallon.... but rather 30 pts per pound per gallon. or b) the stratification issue

[BigPapaG]

There can certainly be variations on gravity contribution from one type/brand lme to another.

Shouldn't vary too much though...

Also, you mentioned steeping grains... were there any with diastatic power such as 2-row, munich etc?
If not, there would not be any apreciable alcohol contribution from the steep, just color and flavor, dextrins and proteins and a gravity contribution from mostly unfermentable sugars. (Edited to correct statement, thanks for keeping me on point bp!)

It's possible if that's the case that whatever calculators you are using were assuming some sort of mash and showing more gravity contribution than actual.

But alas, I digress... Still leaning toward the stratification issue.

[bpgreen]

You'll get a gravity contribution from steeping grains. They add sugars, but the sugars are mostly unfermentable sugars. So they'll add to the og, but they ain't add much (if any) alcohol.

Since you didn't stir, that's the most likely culprit.

[BigPapaG]

My error... Thanks for keeping me on point Bp!

I edited my post to correct.

[jimjohson]

Just spitballin' here; Could the amount you need actually vary from lot to lot? Kind of like paint colors will vary slightly between lots. So the amount of dme/lme needed could on a sliding scale...so to speak

[mashani]

Just spitballin' here; Could the amount you need actually vary from lot to lot? Kind of like paint colors will vary slightly between lots. So the amount of dme/lme needed could on a sliding scale...so to speak

Theoretically the manufacture will list a number like 1.035 gravity points per pound per gallon or something for their extracts. Those numbers should always be close but may not be exact. (you will notice that some places will say "about 1.035 points per pound per gallon").

So yes, it might vary but it should not be a huge difference.

What might also be different is what the brewing software sets it as, IE say QBrew might set it at 1.037 by default if you pick LME. So if your LME is actually 1.035, then it won't calculate it quite right and you might be under by a bit.

[zorak1066]

I think it's a stratification issue. I just brewed a wit with lme and dme and mini mash. target og was 1.05. stirred the heck out of it and did a hydrometer test which said 1.05 on the bean. since the fruit juice test on the hydrometer vs the refractomer was only off by about .002 im chalking it up to the strat...

[BigPapaG]

I think it's a stratification issue. I just brewed a wit with lme and dme and mini mash. target og was 1.05. stirred the heck out of it and did a hydrometer test which said 1.05 on the bean. since the fruit juice test on the hydrometer vs the refractomer was only off by about .002 im chalking it up to the strat...

Yup, Yup!

Glad you got that figured out.

Now get to brewin'!