Not hitting OG

[green_lantern11]

Gents,

Need some help on this. I'm an all grain brewer using a MoreBeer Tippy system. My boil off is 2 gallons for 60min (high, I know). It's a rolling boil. Pre boil gravity is almost always spot on. Let's say 1050 for this example. I boil off 2 gallons and every single brewing program says I should be at 1070. It's always a 20 point increase. But, every time I take my reading it is 1060. That is a big difference and I can't figure out why. I always collect 7.25 gal. I always boil of 2 gal. I always end up with 5.25 gal into the fermenter. I take an OG reading with a hydrometer (adj for temp) and also a refractometer reading that auto adjusts for temp and they both give me the same reading. What am I missing?! This is driving me crazy.

 

[Dynachrome]

Calibration of the equipment/volume measurement?

I don't get that wound up about it. I usually get close based on using my system a-lot.

So, you're reading 1.060, theorwtically? What final gravity are you usually going for? It should still have plenty of alcohol.

 

[Dynachrome]

...oh, and read through some of the threads at the bottom - you titles your thread well. The forum suggests other threads based on your thread title.

 

[billl]

The laws of physics apply at your house too, so you are measuring something wrong.

Do you transfer 100% of the wort to your fermenter or are you leaving hops, trub etc behind?

 

[green_lantern11]

Calibration of the equipment/volume measurement?

I don't get that wound up about it. I usually get close based on using my system a-lot.

So, you're reading 1.060, theorwtically? What final gravity are you usually going for? It should still have plenty of alcohol.

FG should be about 1015. The 1070 and 1060 aren't my real numbers. I was just trying to make this easy. Real #s are: pre boil 1045, OG 1056. With
Target Pre-Boil Gravity: 1.051 Actual Pre-Boil Gravity: 1.045
Target OG: 1.069 Actual OG: 1.056
Target FG: 1.015 Actual FG: (currently fermenting)1.012

My efficiency wasn't so hot this time around, but that should have nothing to do with the point spread during a boil.

 

[green_lantern11]

The laws of physics apply at your house too, so you are measuring something wrong.

Do you transfer 100% of the wort to your fermenter or are you leaving hops, trub etc behind?

I agree, the laws of physics do apply. I'm not reading anything wrong. Post boil volume is 5.33 gal. 5.25 is transfered. I double checked all my readings with both a hydrometer and a refractometer. My volume readings are also correct. I just don't get it.

 

[Dynachrome]

What I was driving at:

Check you hydrometer and your thermometer against other known good devices.

I don't get into that fancy refractometer stuff. My buddy has one and likes it though.

Is there a way to check that alxo?

 

[green_lantern11]

What I was driving at:

Check you hydrometer and your thermometer against other known good devices.

I don't get into that fancy refractometer stuff. My buddy has one and likes it though.

Is there a way to check that alxo?

I have two hydrometers and a refractometer which are all calibrated correctly using distilled water and correct temps. I'm lost brother. Nobody can seem to answer this for me. I forgot to mention that I stir it very well, so it's not a false reading either.

 

[billl]

"I agree, the laws of physics do apply. I'm not reading anything wrong."

One of these isn't true. You've clearly got an error someplace. You are either measuring something wrong or not accounting for a loss. eg 8oz wort soaks hops being left behind. Those are your only options. Calibrate your equipment - hydrometer and refractometer and also double check you site glass.

I also find it highly unlikely you can transfer 5.25 our of 5.33 gallons. Even the lowest hop recipe will lose more than that to hop absorption.

 

[green_lantern11]

The hop absorption really isn't a factor in my system. There is literally nothing left behind as I use a pump to transfer from the boil kettle to the fermenter. I use pellet hops and no bag. The particulates are so fine they go right through the sifter. There is no dead space in my kettle. As far as calibration and taking readings...I agree with you. There has to be an error. That's why I'm in this forum. Hoping one of you can catch what I'm doing. But, as I said, I take two readings for gravity. One hydrometer and one refractometer. Both agree, both are calibrated and both are adjusted for any temperature. My volume is measured with a calibrated stick for that particular kettle. When it was calibrated, I dumped a quart in, made a hash mark, etc. It's all accurate. Please help.

 

[billl]

" It's all accurate. Please help."

There are only 2 options. Either your volumes are wrong or your gravities are wrong. You need to go back to the drawing board with those 2 things and recalibrate. eg if you are pumping, is there any wort left in the pump? Are you getting clean samples - eg not full of break and hop debris. (I know, theoretically, nothing chunky should impact your gravity readings, but in practice and thing sticking to a hydrometer could throw it off). Are you taking a gravity reading from a thoroughly mixed wort or is there potential stratification? Have you recalibrated your "stick" to make sure it's correct? If you are using a Brix/SG refractometer, are you sure the SG side is correct? (my cheapo refractometer uses a linear conversion to SG that gets farther off the higher the gravity goes)

If you are at a total loss, start measuring more. eg. Take gravity and volume measurements every 15 minutes and chart them to make sure you really are tracking the way you think. That should highlight any point in the process where you get thrown off.

 

[Dynachrome]

Interesting related thread...

https://www.homebrewtalk.com/f36/what-your-boil-off-459994/

 

[rmhays25]

Did you ever figure this out? I'm new to brewing, but I do know that specific gravity relates mass and volume. I'm assuming the SG*V is considering mass to be negligible. Since you are boiling off so much water, you may need to account for that change in mass. SG*V/m. Possible to weigh your kettle before and after?