Keep missing OG's

[gotbags-10]

Simple 10g cooler with bazooka screen. Tried single and double batch sparge but still leaving sugars behind. Took a gravity reading yesterday as the last of the sparge runnings were coming out and it was still 1.023! So no wonder I'm missing my pre-boil Gravity. I use a cereal killer grain mill with a credit card gap. I crush slow so I get a very uniform good looking crush. Then the standard 1 hour mash rest at 152. I keep missing my gravities by about 10 points. I've done an extra sparge to get the remaining sugar or but then I end up boiling for 2 hours . Trying to avoid that. Funny thing is when I was using the LHBS crush I never had any issues.

 

[Quaker]

What efficiency are your recipes based on?

Check your thermometer accuracy. I had a low end digital kitchen one which was nearly 10 degrees off.

Any idea what your water profile is or mash pH? My efficiency jumped greater than 10% after switching from well water to RO with salt adjustments and paying attention to pH.

I plan for 70%, but have now been getting 80%, so I need to change my assumptions now. But it's not uncommon for me to have 6 degree Brix final runnings, which is similar to you. The chickens appreciate a little something left in the grains.

 

[gotbags-10]

Basing off of 70% efficiency. I have a mash tun thermometer as well as checking with a thermapen. I use all RO water and build using Bru'n water. Don't have ph meter, hoping bru'n water gets me close enough

 

[FinchSCF]

I know this doesn't exactly answer your question, but I was having problems hitting gravity quite a bit a while ago and discovered this calculator. It'll help you determine how much DME to add if you need to correct your gravity when you take your pre-boil.

http://merrycuss.com/calc/gravityadjustmentextract.html

 

[bowserm]

Maybe mash with more water than you normally would.

I normally mash with 5-6 gallons of water, lauter at 50 minutes and drain the wort. It drains for about 20-30 minutes then I add the remaining sparge water.

Doing this I am consistently getting 80% efficiency.

 

[joshesmusica]

Maybe mash with more water than you normally would.

I normally mash with 5-6 gallons of water, lauter at 50 minutes and drain the wort. It drains for about 20-30 minutes then I add the remaining sparge water.

Doing this I am consistently getting 80% efficiency.

But he's doing a batch sparge, which is when you want to drain quickly.

OP, before going off of a set efficiency, you need to know YOUR efficiency. Beersmith is just a calculator, so you gotta give it the right input before it can give you the right output.

Do this by taking gravity readings and volume measurements at each step of the way. In the end, the point is to get consistent efficiency. Obviously if you can get that higher, it's probably a good thing, but there's no need to make it a pissing contest. It's much better to consistently get 65%, than getting 85% one time, but 70% the next. So just measure, measure, measure. Then once you figure out what your efficiency is consistently, you can put that into beersmith, and you'll be hitting your numbers much better.

How's your FG calculations going though? I know mash temps aren't going to be the only thing to affect that, but it is certainly one factor.

As far as mash volume and sparge volume, I think a lot of people are talking about having equal volumes when doing batch sparges. Or at least that the amount drained off would be equal. So let's say you're losing .5 gallon to grain absorption, and you want 6 gallons in your BK, then you would mash in with 3.5 gallons, then sparge with 3 gallons.

 

[doug293cz]

Simple 10g cooler with bazooka screen. Tried single and double batch sparge but still leaving sugars behind. Took a gravity reading yesterday as the last of the sparge runnings were coming out and it was still 1.023! So no wonder I'm missing my pre-boil Gravity. I use a cereal killer grain mill with a credit card gap. I crush slow so I get a very uniform good looking crush. Then the standard 1 hour mash rest at 152. I keep missing my gravities by about 10 points. I've done an extra sparge to get the remaining sugar or but then I end up boiling for 2 hours . Trying to avoid that. Funny thing is when I was using the LHBS crush I never had any issues.

Actually, a 1.023 SG for runnings after a double batch sparge is right in range. You can't really do any better than this, and it represents a lauter efficiency of 87% - 88%. Your actual mash efficiency will then depend on your conversion efficiency (mash efficiency equals conversion efficiency times lauter efficiency.)

Can you describe your mash and sparge processes in detail? Doing so might help the folks here pick up on anything that might be affecting your efficiency.

But if your lauter processes are all optimal, then your problem would be low conversion efficiency. You can measure conversion efficiency by checking the SG of the wort in the mash, and comparing it to the chart here: http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Measuring_conversion_efficiency.

Brew on

 

[RM-MN]

If you have never had trouble draining your mash tun, try tightening you mill a bit. Your slow milling with the credit card gap may be leaving you with too big of particles.

 

[guillaume]

Have you tried to put your numbers into this? http://braukaiser.com/download/batch_sparge_simulator.xls

How long do you let it rest after adding sparge water?

As for the milling, I'm using the same killer grain mill but never had problems with draining my kettle (8g pot with false bottom) with a credit card gap. So on my next brew I wil set it to the smallest gap (0.25 on both sides). I spray a little of water on my grain before milling it to soften the outside. I'll see if it makes a difference but at least the crush sample I made looks better than the credit card gap.

Do you test first running with iode?

 

[doug293cz]

...
How long do you let it rest after adding sparge water?

...

Do you test first running with iode?

A good stir (several minutes) after adding sparge water is more effective than a rest. All you are trying to do with a batch sparge is equalize the sugar concentration throughout the wort prior to run off. The shear forces of stirring are more effective at this than is waiting for diffusion to occur during a rest.

The iodine test can mislead when sampling only the wort. There can be starch left in the grain, and the wort will show no starch. Checking the SG of the wort in the mash is less likely to lead to false conclusions about the completeness of the mash. For the iodine test to be valid, you must remove some of the grain with the wort, and crush up the grain to expose any remaining starch that may be trapped in the centers of the grits.

Brew on

 

[guillaume]

A good stir (several minutes) after adding sparge water is more effective than a rest. All you are trying to do with a batch sparge is equalize the sugar concentration throughout the wort prior to run off. The shear forces of stirring are more effective at this than is waiting for diffusion to occur during a rest.

The iodine test can mislead when sampling only the wort. There can be starch left in the grain, and the wort will show no starch. Checking the SG of the wort in the mash is less likely to lead to false conclusions about the completeness of the mash. For the iodine test to be valid, you must remove some of the grain with the wort, and crush up the grain to expose any remaining starch that may be trapped in the centers of the grits.

Brew on

Funny, usually people say to only use liquid no particles for iode test.

For batch sparge, I usually give it a good stir (3-4 minutes) then let it settle down slowly. You're saying we should stir and drain immediately?

 

[doug293cz]

Funny, usually people say to only use liquid no particles for iode test.

For batch sparge, I usually give it a good stir (3-4 minutes) then let it settle down slowly. You're saying we should stir and drain immediately?

As far as efficiency is concerned, you can drain immediately after stirring. However, you can let the grain bed settle, and vorlauf before draining, if clear wort makes you feel better (cloudy wort doesn't cause cloudy beer.)

Brew on

 

[RM-MN]

Funny, usually people say to only use liquid no particles for iode test.

For batch sparge, I usually give it a good stir (3-4 minutes) then let it settle down slowly. You're saying we should stir and drain immediately?

When you test with iodine and use only wort you are testing for conversion. If you include the grain particles you can test for efficiency, the ability to get all the starch to convert. With small grain particles you can get the starch to convert because the water can access the center of the particles but if your efficiency is low it is most likely that the grain particles are too large to get wetted all the way to the center leaving unconverted starch there.