Mash Completion

I just brewed and IPAA yesterday didn't get the gravity points I was looking for, how do you test to see if the mash has completely converted. I mash that 146° for 90 minutes. My gravity points were supposed to be an OG of 1.076, But my OG was 1.068. Any ideas on what happened?

more than likely the grain crush was not great, or water chemistry was possibly off.... those would be two possibilities. Could also be something as simple as final volume of liquid was more than planned, or temperature of sample was not at room temp...

How much grain did you use to how many gallons of wort did you finish with?

You can test for conversion w/ iodine. Put a small amount of wort from your tun in a container. Add a couple of drops of iodine. If it turns black conversion is complete.
Also, if you mash at 146 for 90 minutes how do you insure you're maintaining that temp for so long ? Only a few degree drop could impact your conversion. Also, what temp is your sparge water? Do you pre- heat your mash tun?

Iodine actually stains purple/black in the presence of starches. That would indicate conversion had NOT taken place. When added to the wort, iodine should maintain its normal color if conversion has completed.

Also, check your mash after you drain all your runnings. If the grain tastes sweet or you find dough balls, you know that you didn't achieve full extract potential in the tun.

Sorry, you're absolutely correct - I hadn't finished my morning coffee while typing!

Every 20 mins I was checking my temp it stayed constant through out. I ended with 5.5 gals. I do not pre heat my tun. I think conversion wasn't complete. I need to get iodine to try that test. Thanks for the info

Worst case scenario is my imperial IPA just turns into an IPA hopped like an imperial IPA lol!!

90 minutes is an extraordinary long time for conversion to not be complete - there is some additional thing going on. Under ideal conditions, I have heard many people talk about 30 and 40 minutes to get almost complete conversion.
There has to be something else - crush, mash ph, temp, malfunctioning hydrometer..... something. 146 seems on the very low range for mashing.... 148-152 seems to be the more common range.

I'll check my notes but I'm pretty sure 146 is what I had written down. I also do notice time to time again that my hydrometer is sticking to the side of the test tube. Don't know if that's giving me false readings or not, also looking into getting a refractometer to help get better readings!!!

The starting mash temp I have a my note was 148 and by the end of the 90 minutes I was down to 146 I'm not sure if mash was completed and not thinking maybe hydrometers no good!

You can use Kai's table to check conversion efficiency:



This is theoretical maximum that can be extracted so you don't have to get these numbers, anything above 90-95% is good.

More info:
http://braukaiser.com/wiki/index.ph..._Efficiency#Determining_Conversion_Efficiency

Couple more thoughts -
*Higher gravity mashes usually result in lower efficiency.
*Mash not mixed well - dough balls.
*Channeling of sparge water through grain bed.

In my experience, 1.07's is where I start losing some efficiency compared to what I am used to on lower gravity beers. I routinely get 80% efficiency in the 1.04-1.06 range. As soon as I go for 1.07's though, I tend to start falling short of that same efficiency.

I would test the hydrometer though, just in case.

To be honest it's my try at a higher gravity beer. U shouldn't be surprised that I didn't hit my number like I'm used to on my lower gravity beers. This has just caused me to dig deeper into books and ready and try to understand what might have gone wrong along with everyone's advise!

It is pretty normal to have lower efficiency with HG beers.