To stir mash or not to stir?

On pages 203-205 of the latest edition of How to Brew, John Palmer says to stir the mash to ensure all sugars are rinsed out. Weather fly or batch sparging I thought the grain bed should be left alone to act as a filter. Both methods seem reasonable but opposites.

Helping a friend make an all grain to day so any thoughts would help.

Either way you would stir real well and let settle a few minutes prior to (each if batching) sparge...once sparging "let her be" .

I batch sparge so stir then wait 5 min for it to settle some what then vorluf then let it drain.... I would think to stir would be the best to rinse all the sugar. As long as you re set the bed no biggie.

Can't think of a single reason not to stir the mash at some point. Like others have said. Stir while mashing. When it comes time to sparge, leave it alone. The only draw back to stirring while mashing in a cooler is the loss of heat every time you take the lid off. So, doing it once or twice.

Agreed. Stir REALLY WELL when everything first goes in - doughballs don't work - "each grain must be thoroughly wetted". I usually just stir once or twice during the mash as Hammy said - just to ensure no doughballs or cold spots and because it smells AWESOME. Then I stir at the end, give it ~5mins to settle, vorlauf & batch sparge.

I think the most important stir is right when you first add the grain. The second most is when you add your sparge water for single batch sparging - gotta make sure everything is rinsed. But no stirring once you open the valve & start running off. If you must stir, let it settle & vorlauf again.

I thought stirring releases unwanted starch, tannins etc. scratching my head now !

Hmm...I've never had an issue with that, but I've never tested it one way or the other.

I'm not stirring it like I'm beating egg whites or anything, more like making gravy - I stop once the doughballs are gone and once sparge water is nicely mixed.

Sure, while you're introducing your grain to the water you need to make sure all the grain gets water. But, while sparging, why wouldn't you stir? Just be careful not to beat it to death. You wouldn't want to break down the grain any further and have it transfer into your kettle.

I was thinking that you were stirring throughout the sparge. I was told to only stir to mix well and to even out temp, let mash for a hour then fly sparge without touching grain bed. So you stir again before the sparge ? It makes sense to me, but I wonder now why I told not to stir. Huh !

Jamming said:

I thought stirring releases unwanted starch, tannins etc. scratching my head now !

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If you have starches that can be released by stirring you didn't get good conversion in your mash. That could be due to a poor quality of crush, wrong temperature, or not long enough mash time.

To extract tannins you have to let your mash get too alkaline and have too hot of water to sparge with. If you use boiling water and sparge multiple times to try and get better efficiency you could get the grain bed to lose its acidity and extract tannins. If you mash is acidic you cannot extract tannins or if your water is below 170 F you cannot extract tannins.

RM-MN said:

If you have starches that can be released by stirring you didn't get good conversion in your mash. That could be due to a poor quality of crush, wrong temperature, or not long enough mash time.

To extract tannins you have to let your mash get too alkaline and have too hot of water to sparge with. If you use boiling water and sparge multiple times to try and get better efficiency you could get the grain bed to lose its acidity and extract tannins. If you mash is acidic you cannot extract tannins or if your water is below 170 F you cannot extract tannins.

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Oh ok thanks for explaining, makes sense, more of a overheating issue then. Going to stir my next brew, last time I didn't and hit my numbers ok, but will give it a try.

Jamming said:

I thought stirring releases unwanted starch, tannins etc. scratching my head now !

Click to expand...

I would think the BIAB folks indirectly dispelled this belief. They have pretty well established that squeezing the cheezits out of the bag has no ill effects. So stirring should not either.

I stir three times during the mash. I double batch sparge, and stir with each water addition. Rest 5 to 15, set the bed and drain. My second batch is typically between 10 and 20 points, so should also be high enough not to leach bad stuff. So far so good.

Thank you all. Didn't get these replies until the mash had been sitting for 45 min so stirred the mash once and again just before sparging. Did an iodine test and got no purple. Hit estimated OG from recipe based on 75% efficiency so very happy.

Note: Efficiency was 51% 2 batches ago, made some changes and last batch was 59%. As I said, this batch was 75% so stirring worked awesome.

I mash overnight in my coolers and only stir the mash when I add the grain to the water. I stir it up for about 30 seconds to make sure all the grain is in suspension and don't stir it again. Works great.

Imperial, I was definitely in the same boat as you with very poor efficiency on my first batch (intended to do a 10gal batch, ended up with 7gal of wort at the target OG). I tried to leave the grain bed intact and keep water above the grain, but it never seemed to rinse the grain sufficiently. Second batch after mashing I vorlauf'ed the wort, drained out pretty much completely. Then I infused the batch sparge water, stirred, let settle for a few minutes, vorlauf'ed, drained pretty much completely and repeated once more. Then I bought beersmith and its apparently that's what I was supposed to do for a batch sparge anyway.

In my experience, stirring is good.

Stirring very well at dough in is crucial, and it often takes more/longer stirring than people think to fully incorporate the mash water and eliminate all doughballs. Stirring before sparging isn't really necessary if you do a fly sparge properly, but doesn't hurt any either. Stirring very well with each sparge water addition is crucial if you're batch sparging, since that's the mechanism that gets the sugars into solution. I've also never seen a benefit to letting the grain bed "settle" before draining when batch sparging. It requires a little more vorlaufing if you start draining immediately, but it's still a lot quicker than waiting 5-10 min. I've never seen any benefit to stirring during the mash, and unless you're using a RIMS/HERMS/etc., it usually results in a temperature loss. As always, YMMV.

Rigs, I too have Beersmith. Where did you find the instructions that tell you to stir when batch sparging?

Juan, I found stirring the mash to help, but then I only stirred it once. Palmer recommends stirring more often. Also lost temp in the process. Plan to have hot water on hand next time. What is "RIMS/HERMS/etc." I am new to brewing and have not heard these terms before.

As I posted earlier I hit the estimated OG of 1.064 from a recipe with 75% efficiency. Maybe a dumb question but does that mean the mash had an efficiency of 75%? I think it does but just want to make sure I am not misreading something.

I stir while doughing in and twice over the hour long average mash. I basically open it up and stir 20 minutes in then again at 40. I don't want to stir it much more than that because I don't think it would matter much and I would risk losing the temp. I double batch sparge and stir after each sparge water addition and wait 5 or so minutes befure vorlaufing and draining for the grain bed to settle. Been working fine this way so far, though I'm still uber new to AG.


Rev.