Great improvement in efficiency.

[BobBailey]

I read somewhere, probably here, that stirring the mash would yield greater efficiency. I stirred my last 2 mashes and was amazed at the improvement.

I use the Beersmith2 default setting of 72% overall efficiency. and usually miss estimated OG by 2 to 4 points if I hit my post boil volume. The first batch I stirred once about half way through the mash and hit estimated OG right on the button. The last batch I stirred every 15 minutes and was amazed when I over shot the 1.046 estimate by 5 points and came in at 1.051. WOW! Over 10%--amazing. Same basic recipe and post boil volume was as estimated.

Just thought I'd post in case anyone hadn't seen previous posts on the subject. Thanks to whoever originally posted the subject.

Bob

 

[rlynge]

Interesting, I might have to try this....anyone else use the stir method?

 

[homebeerbrewer]

This is interesting, but there are several factors that can effect efficiency. Was there anything else different in the last batch than prior batches?

I may have to try this method myself, but I get a consistent 80% efficiency now. Do I really want to go higher?

 

[rico567]

I don't find it necessary to stir during the mash. I stir like mad when I mash in, but then the lid goes on until I start lautering 60 minutes later. I hit my OG with almost monotonous regularity.

 

[Stephonovich]

I stir the mash a few times throughout while I'm checking temperatures, to ensure even heat distribution. Other than my first couple of batches, I hit my OG within 1-2 points every time. My efficiency is around 75%. I batch sparge, for reference - I'll probably be moving into fly sparging soon.

 

[PhelanKA7]

I had read somewhere that it was important to stir about every 20 minutes during a mash in order to eliminate hot/cold pockets.

 

[rico567]

I had read somewhere that it was important to stir about every 20 minutes during a mash in order to eliminate hot/cold pockets.

If I stir my mash thoroughly before putting on the lid and walking away, how are hot/cold pockets going to form? I stir my mash for several minutes when I start (and I pretty much have it figured out with my system what the strike water temperature has to be to make the mash temperature come out right), and then I check the temperature, button up the MLT, throw a furniture pad over it, and go do something for an hour. When I come back, I inevitably have full conversion of the malt. So how would I benefit from periodically stirring the mash?

 

[coldrain]

If I stir my mash thoroughly before putting on the lid and walking away, how are hot/cold pockets going to form?

IMO the type of mach tun would make a difference. Mine is a steel kettle and brew outside in Seattle area. I need to add heat and stir because the cold air and wind cools the edges of mash while center stays warm. I would think an Igloo cooler mash tun would stay much more stable and benefit less from opening it up and stirring.

 

[tre9er]

In terms of hot pockets, the center is always going to be hotter than the sides in most tuns because the heat dissipates from the edges while the center is buffered by grain around it. I would like to experiment with putting rigid foam or something similar on top of the grain bed to keep heat from dissipating from the top of the grain bed, causing it to be cooler.

 

[Naptown]

IMO the type of mach tun would make a difference. Mine is a steel kettle and brew outside in Seattle area. I need to add heat and stir because the cold air and wind cools the edges of mash while center stays warm. I would think an Igloo cooler mash tun would stay much more stable and benefit less from opening it up and stirring.

Great example, I would have to assume the same.

 

[tre9er]

I want to build a stirring apparatus inside the tun with a crank handle on the top, maybe. Then I could stir without opening. Of course, any thermometers inside wouldn't fare well...

 

[cpatel479]

I was thinking about stirring the mash just the other day. I was reading appendix F in Palmer's 'How to Brew' where he talks about manifold construction and says that depending on the number of pipes and spacing, some of the grain is over sparged and some is under sparged. So I was thinking that if you stirred and then re-vorlauft, that should help ease the under/over sparging. Looks like you have verified that for me. Can't wait to try it on my next brew day. THANKS!

 

[tre9er]

Well I would certainly stir after each batch sparge addition, re-vorlauf, then drain. Stirring during the mash could also have benefits if temp loss isn't occurring in the process.

 

[BrewinHooligan]

I find this very interesting too... I used to stir my mash periodically and the last batch I did not as I was loosing too much heat opening my cooler and stirring. I stirred like mad when I doughed in until I hit my target temp, then closed up and covered with a blanket. At the end of the mash, I stirred again before vorlauf. Then I batch sparged with 180f water, stirred like mad befre vorlauf and drain, and hit 5% higher efficiency than when I stirred every 15 minutes during the mash. My grain crush could have been a little different and my sparge water was hotter than I had used in the past so there are a few more variables in play.

 

[rico567]

In terms of hot pockets, the center is always going to be hotter than the sides in most tuns because the heat dissipates from the edges while the center is buffered by grain around it. I would like to experiment with putting rigid foam or something similar on top of the grain bed to keep heat from dissipating from the top of the grain bed, causing it to be cooler.

I understand that there will always be some temperature gradient from the center to the edges of the cylinder represented by my mash. The relevant questions are:

1. How much is the gradient?

2. Is it enough to make any significant difference in the outcome of the mash?

So far, my answers are, #1: since I only lose 2-3 degrees overall in a 60 minute mash, not very much. #2: since I hit the high end of my numbers all the time (OG, FG), apparently not.

My conclusion: Any amount of temperature equalization to be gained by intermittent stirring in the course of the mash is unlikely to produce a significant result.

 

[bk0]

Don't most huge commercial MLTs have automatic stir arms? Seems like they wouldn't build them unless there was a good reason...

 

[tre9er]

Don't most huge commercial MLTs have automatic stir arms? Seems like they wouldn't build them unless there was a good reason...

I've seen home brewers who do larger, more "slick" brewing make these too...figure they must have a good reason. Now, is it worth the trouble for us small-batch guys? That's debatable.

 

[BobBailey]

If I stir my mash thoroughly before putting on the lid and walking away, how are hot/cold pockets going to form? I stir my mash for several minutes when I start (and I pretty much have it figured out with my system what the strike water temperature has to be to make the mash temperature come out right), and then I check the temperature, button up the MLT, throw a furniture pad over it, and go do something for an hour. When I come back, I inevitably have full conversion of the malt. So how would I benefit from periodically stirring the mash?

I should have mentioned that I generally mash in at 148 to 150 and use a 10 gallon round rubbermaid cooler. I do stir thoroughly at the beginning too.

I believe cooling around the sides was the reason for efficiency losses. The core temperature of the mash was holding even when I mashed for 90 minutes before. With a quick stir every 15 minutes I now lose 2 degrees in 45 minutes. At higher mash temperatures I don't think stirring would make nearly as much difference.

 

[PhelanKA7]

If I stir my mash thoroughly before putting on the lid and walking away, how are hot/cold pockets going to form? I stir my mash for several minutes when I start (and I pretty much have it figured out with my system what the strike water temperature has to be to make the mash temperature come out right), and then I check the temperature, button up the MLT, throw a furniture pad over it, and go do something for an hour. When I come back, I inevitably have full conversion of the malt. So how would I benefit from periodically stirring the mash?

I understand your point. I've only done two AG batches thus far so I am by no means an expert. I do know that my first batch I got somewhere around 60% efficiency and mashed for 60 mins only stirring once at the mash in. My second batch I stirred vigorously for about 20 seconds every 20 mins during the mash and got about 83% efficiency. But there could have been a myriad of different things that could have caused this disparity as i understand it.

 

[Rogsterman]

I wonder which method of sparging would be best to get the most yield?

 

[PhelanKA7]

I wonder which method of sparging would be best to get the most yield?

I got that 83% efficiency doing a fly sparge.