BIAB, mashing out. How much can that increase efficiency?

[Denny]

I did extract brewing when I started and 170F was the magic number to not go above when steeping the specialty grains due to risk of tannin extraction.

Doesn't tannin extraction have something to do with volume of the grains? With the small amount of steeping grains used in extract, I always thought that was the reason it was easier to have tannins produced when going over 170?

Yeah, that's true. Because you have less grain to lower pH, tannin extraction is a bit more likely. That's why I recommend people use a ratio similar to mashing for steeping.

 

[zacster]

I always raise my mash temp up to 168 at the end and then pull the bag as well. It seems to work well and I get good efficiency. And as everyone else has noted, efficiency varies with the OG, with low gravity beers getting my 80%+, and higher gravity around 70.

I pull the bag and rig up some kind of drainage system using a large flat container and a baking pan inclined inside of it. I just squeeze against the baking pan and the run-off collects at the bottom. Based on some of the comments, I may try to keep a little water back to use as sparge water. That seems like a good idea, as long as it doesn't lower the efficiency of the main pot.

 

[Euphist]

So, this last brew I decided to do an experiment.

At the end of my mash time, I gave the mash a good stir and took a reading. 10.2 brix

I then raised the bag off the bottom, fired up the burner, and brought it up to 168 before pulling the bag. 10.8 brix

Squeezed the dickens out of the bag and dumped in the results. 10.8 brix

So, I realize that these are one time results, and that they do not prove that the increase in sugar is due to temperature rather than time. However, it is enough evidence for me to continue what I have been doing. It also would indicate that draining and squeezing the bag only increases volume not efficiency. However, since I get about another 1/2 gallon from that, I will continue to do it as well.

I plan to repeat this on my next few brews to verify my results. It's only a few drops more wort and a couple of seconds, so why not?

 

[ArcLight]

...

It also would indicate that draining and squeezing the bag only increases volume not efficiency. ...

I don't agree. If you squeeze you get more volume with sugar in it. Same for sparging. You can then evaporate this water and end up with a higher OG.

Squeezing + sparging give you more total sugar, though the sparge wort is weaker than the main wort. Which is why I don't mash in all the water, and instead hold some back.

Using BIAB take 15 pounds of grain and mash in 8 gallons. Then raise teh bag and take a reading.

Later on take mash 15 pounds in 6 gallons, pull out the bag, squeeze/drain, then put it in 2 gallons of water for 5 minutes, while stirring, pull out the bag, squeeze, and add in the runnings, and take a reading. I'll bet you the 2nd wort has a lot more sugar, even though both are around 6.5 gallons.

 

[wilserbrewer]

Later on take mash 15 pounds in 6 gallons, pull out the bag, squeeze/drain, then put it in 2 gallons of water for 5 minutes, while stirring, pull out the bag, squeeze, and add in the runnings, and take a reading. I'll bet you the 2nd wort has a lot more sugar, even though both are around 6.5 gallons.

I have also found that even ghetto sparge seems to result in less residual sugar left in the grain.

Lately I have been reserving a small percentage of the mash water, say a gallon for an 8 gallon batch and slowly pouring it over the bag as it is suspended over the kettle.

I don't have any hard evidence, but my spent grain no longer has a sticky feel to it...the grain bag seems better rinsed, that's the ultimate goal simply put. Even a couple quarts of cold water will work FWIW.
cheers!

 

[seckert]

i do the same thing. i use less water than i am going to need and i do the ghetto sparge. i use a colander to spread the water evenly across all the grains so i rinse them all off. i think if you dont do this then you are missing out on the sugar left on the grains. besides you need to add water to bring you up to your pre-boil volume so why not do it?

 

[Euphist]

I don't agree. If you squeeze you get more volume with sugar in it. Same for sparging. You can then evaporate this water and end up with a higher OG.

Squeezing + sparging give you more total sugar, though the sparge wort is weaker than the main wort. Which is why I don't mash in all the water, and instead hold some back.

Using BIAB take 15 pounds of grain and mash in 8 gallons. Then raise teh bag and take a reading.

Later on take mash 15 pounds in 6 gallons, pull out the bag, squeeze/drain, then put it in 2 gallons of water for 5 minutes, while stirring, pull out the bag, squeeze, and add in the runnings, and take a reading. I'll bet you the 2nd wort has a lot more sugar, even though both are around 6.5 gallons.

Sorry, I didn't really think out what I was trying to say. My point was that performing a mash-out increased my pre-boil gravity, whereas squeezing resulted in an increased volume of the same gravity.

As far as sparging goes, it defeats my purpose for going BIAB in the first place. I am a firm believer in the KISS theory. A second vessel and additional steps kind of goes against that. Besides, when I'm running 85-95% mash efficiency, I don't see it being worth the effort.

Don't get me wrong...if it works for you, great...keep on making and drinking great beer.