I gave up the 10% efficiency to save 30+ minutes. I was also worried about over-sparging. From the forum and reading I found that over 85% was not particularly a good thing.
On the teig side, I’ve only experienced this in quantity with multi-step mashes or when I perform a protein rest.
You might want to let Sierra Nevada know. They aim for, and achieve, nearly 100% efficiency.
Given their quality control, I can see how maximizing efficiency would be an advantage to a professional brewer in a professional brewery. For the homebrewer, I’ve had numerous very experienced brewers tell me not to shoot for it as you run the risk of over sparging and extracting tannins.
To each their own, but I think comparing even a very experienced home brewer to Sierra Nevada is a major stretch…if we could all brew like Sierra Nevada, there would not be a Sierra Nevada.
Dave
Yeah, I agree with you…I seldom compare commercial operations to homebrewers. But my point was that high efficiency doesn’t necessarily cause problems. My average efficiency runs about 85% and I sometimes get up into the 90s. I don’t get astringency from tannins because of it. Taking advice from experienced brewers is a great thing, but you should always check it our for yourself.
Sierra Nevada has a mill with large rollers that shears the grains and leaves the husk mostly intact. They also have 5.5 ph water throughout the brewery. With that pH the tannin extraction will be minimal.
Edit - the brewers that hammer mill the grains and have a mash press get >100% efficiency.
Good info Jeff. How is it that you can get >100%? What makes up the calcs?
I also can see that if the process is sound, the PH correct and sparge water at the right temps, there is nothing wrong with over 85% efficiency. I dialed mine back on some advice when I was getting 85%+ every batch, but I do not remember ever getting any astringency. Sparge on if you like it that way!
I do like my consistent 80% and cutting the brew day down 30+ minutes though…
Dave
The Congress mash is the referrence. Milled to a fine flour, mashed in distilled water, drained through a filter IIRC, feel free to correct this if you know more.
The hammer mill get it very fine, and the mash press squeezes the mash between the filter plates that give a large area. They get it all out through pressing the mash, so they can exceed the Congress mash.
These are popular in Belgium. I have talked to local brewers that would love to have one, and there is a new place going up that has one ordered for the system.
How the heck does one lauter grain that has been hammer milled? I’m trying to picture a 200 barrel vessel using the brew-in-a-bag method. 
It is pressed not lautered. This may help. Squeezed horizontally and the liquid drains out the bottom.
http://appellationbeer.com/balancing-nature-tradition-and-progress-in-alaska/
Here is another brand.
Excellent article. Thank you.