[trapae]

Not that this really matters........

I have consistently been getting more 1st running volume than I should even though I have correct grain absorption and dead space variables.  My 2nd runnings are always right on.  Also, my volume markings on my Ss mash tun are off by about 0.25gal.??

Figured it out.

Turns out that I have been measuring my strike volume at room temperature, then heating it up, transferring it to the MT, and proceeding.  Turns out I hadn't thought about the thermal expansion gain in volume which is probably near 0.25gal which pretty much corrects everything.  So now I will heat first, then adjust strike volume.

Not that it matters because I just adjust sparse volume dependent on 1st runnings, but I am OCD.  Academic I know.

[denny]

Thermal expansion at boiling is about 4%.  Hardly enough to measure.  Are you certain that's it?  Keep in mind that you aren't heating to boiling and the water would cool down.

[brewsumore]

If you have tried and corrected your estimation, then congratulations.  Of course it's easier to predict the sparge runoff, since the grains have already fully absorbed all the liquid.  After 12 years of batch sparging (Denny-style), i still struggle to hit combined runoffs volume exactly.  I don't worry about it, and am pretty accurate.  Brew on, brew strong!

[trapae]

I didn't know it was only 4%. The reason I thought about it was on BeerSmith, in my equipment profile there is a cooling volume loss of around .28 gallon for around 6 gallons of wort. I thought the thermal expansion would be similar. Maybe it is my grain absorption or dead space I have to adjust.  Either way using the Denny method I just have to adjust my spark water and it still works out. Just overthinking it probably.

[Stevie]

That's about 4%

[denny]

That's about 4%

Except that happens at boiling (I believe) and he doesn't get anywhere near that.

[denny]

I didn't know it was only 4%. The reason I thought about it was on BeerSmith, in my equipment profile there is a cooling volume loss of around .28 gallon for around 6 gallons of wort. I thought the thermal expansion would be similar. Maybe it is my grain absorption or dead space I have to adjust.  Either way using the Denny method I just have to adjust my spark water and it still works out. Just overthinking it probably.

Don't assume any of the defaults in Beersmith necessarily apply to you.

[Stevie]

That's about 4%

Except that happens at boiling (I believe) and he doesn't get anywhere near that.

Sure. I get maybe a pint between sparge and boil.

[HoosierBrew]

I didn't know it was only 4%. The reason I thought about it was on BeerSmith, in my equipment profile there is a cooling volume loss of around .28 gallon for around 6 gallons of wort. I thought the thermal expansion would be similar. Maybe it is my grain absorption or dead space I have to adjust.  Either way using the Denny method I just have to adjust my spark water and it still works out. Just overthinking it probably.

If your dead space is measured accurately and your runoff volumes are still a little high, reducing your absorption figure is easy enough. A lot of brewers start off using ~ .12 gallons/lb as their absorption figure, and modify as needed until runoff amount is accurate. Probably sounds dumb and obvious, but double check that you're measuring your water volumes accurately. I often round up volumes to even gallons when possible, but when I use partial gallons to mash, I have a plastic pitcher with graduated amounts on it that helps keep me accurate.

Admittedly, I'm OCD (or is it CDO) about my brewing, but not everyone needs to be. A point or two high or low on OG is just not that big a deal. Good luck!

[Pricelessbrewing]

Here's my thermal expansion calculator, works at any temp using thermal expansion of water (not sugar solutions, since that math is much more complicated).

https://pricelessbrewing.github.io/BiabCalc/Thermal.html

What HoosierBrew said, looks like youre volumes still aren't lining up. Either your absorption rate is lower than input, or your initial volumes weren't measured accurately.

[trapae]

Cool, thanks all.

[brewsumore]

I didn't know it was only 4%. The reason I thought about it was on BeerSmith, in my equipment profile there is a cooling volume loss of around .28 gallon for around 6 gallons of wort. I thought the thermal expansion would be similar. Maybe it is my grain absorption or dead space I have to adjust.  Either way using the Denny method I just have to adjust my spark water and it still works out. Just overthinking it probably.

If your dead space is measured accurately and your runoff volumes are still a little high, reducing your absorption figure is easy enough. A lot of brewers start off using ~ .12 gallons/lb as their absorption figure, and modify as needed until runoff amount is accurate. Probably sounds dumb and obvious, but double check that you're measuring your water volumes accurately. I often round up volumes to even gallons when possible, but when I use partial gallons to mash, I have a plastic pitcher with graduated amounts on it that helps keep me accurate.

Admittedly, I'm OCD (or is it CDO) about my brewing, but not everyone needs to be. A point or two high or low on OG is just not that big a deal. Good luck!

I leave my grain absorption set at .12 in ProMash.  I'm sure that big kernel vs. small kernel malt, addition of adjuncts, etc.  messes with it for different brews.  I am pretty basic in that I use a marked 1/2 gal pitcher to transfer my strike water to my mashtun - typically at least 10 gal of water per brew (I make 10-gal batches).  Like I said, I'm used to minor variance in kettle fill, but it's never a problem.  I use a gradated spoon inserted in the kettle to tell me when the timed boil begins, usually at the first hop addition.