# Stirring the mash with a herms system?



## Truman42 (14/3/13)

Gday Gents,

I just want to run my mash procedures by you to see if Im doing it right or if I could improve on my current procedures. Im getting around 65-70% on average gravity brews of around 1.050 start gravity.

I use a 3V system with a herms coil

1. Heat water in HLT to strike temp and drain to mash tun (keg with domed stainless mesh false bottom)
2. Dough in at a ratio of around 3:1 adding half the grain, stirring then adding the rest and stirring again.
3. Start pump which recirculates through the herms coil and back to the mash tun and Im using a T piece on the end of my hose with a loop of hose that has slots cut into it as my mash return.
4. Raise the temp on my herms to ramp up to the next step as per the recipe. (pump runs for the entire mash)
5. Raise to 75C for 10 min mash out then transfer to kettle until pump runs dry.
6. Add half of my sparge water at a temp of 82C. Stir for a few minutes then recirculate for 10 mins.
7. Transfer to kettle then repeat for second batch sparge.
8. Begin boil.

Ive been reading about stirring the grain at least a couple of times during the mash but seems to be done only with non recirculating systems such as BIAB etc.

I was advised not to bother stirring as im recirculating my wort, which will allow the enymes to move through the grains and convert the starches. Although Ive never had a stuck sparge, Ive considered that this recirculation for 90 mins might be compacting the grain bed and causing the enzymes to be "locked" in place so to speak and not be able to freely move around in the mash.
Obviously when I sparge and give it a stir Im freeing this up but as Ive already done a mash out wouldn't I only be freeing up sugars already converted and thus ending up with a lot of starch that wasn't able to be converted by the enzymes?

So would a stir of the mash at regular intervals, (say each time I ramp up) be beneficial? Do other herms brewers here stir their mash at all? Have you noticed a difference in efficiency compared to if you havent stirred?

Yes I could do this in my next brew as an experiment but would like to know if others have done this and what their findings were.

If I did my last stirring while ramping up to a mash out step the ten minute mash out should be enough recirculation to filter the wort through the grain bed as it is during my sparge steps.

(Yes I searched and most posts related to stirring BIAB or non recirculation mash, didnt find anything on stirring a herms or rims mash)

Thanks in advance gents for those willing to offer some good helpful advice.


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## browndog (14/3/13)

Truman, I do exactly the same as you, however, I stir after adding the first and second sparges. On my old system this used to give me about 80% efficiency, on the new, somewhat less due to the physical design of it. logially speaking you are using mehcanical action (stirring) to help rinse the sugars from the mash. If you are chasing better efficiency then do it as you only have to recirculate for a few minutes to get the wort flowing cleanly again.


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## hsb (14/3/13)

Same here - only stir at dough in and at sparge.
I mash a bit thinner - 4l/kg and also am extra cautious not to compact the grain bed.
I let it sit for a good 10 minutes following dough in - this is normally just my first rest - then begin recirculation.

Compacted grain bed sounds like a separate issue to efficiency/stirring, though they are obviously related in their effects.

I can only speak for my setup/experience, but I feel that all the grain gets a mighty good washing through a 90 minute recirculation.
I normally hit 75% and that is all I'm after myself.

You might consider your crush as a factor as well.

Having said that, I don't see the 'harm' in stirring more, you just have to wait for your grainbed to resettle, or be mindful that you're more likely to cause it to compact when you pull the grain down from being in suspension with the pump.

To me, you're either stirring/agitating the grain, or your recirculating the liquor through it, both to the same end, but never both at the same time YMMV though.

65-70% sounds all right to me. I just CBF chasing efficiency points beyond 70%, grain is cheap, life is short ;-)


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## Truman42 (14/3/13)

@browndog... I also stir between at the start of the first and second sparge? How long do you sparge for each time? 10 mins?

@hsb... I'd be happy with 70% but more often that not its around 65%. Would like to get that extra 5% consistently.


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## QldKev (14/3/13)

I only stir after I've gotten pretty close to mash out. Once I've given it a stir I leave it for at least 10min until the wort clears up fully. Then once all my batch sparge water is added I give it a second stir, and once again give it at least 10mins. So only 2 stirs for the entire brew. Most my beers are only 1.040 OG, but I get around 85% efficiency.

I don't stir upfront of the mash as I underlet the mash water, so dough balls are not an issue.

I think a big % of the efficiency comes from the crush and the sparge. Crush needs to be fine enough so not too much sugar is caught in the sparge, and the sparge needs a good stir to mix into suspension all the sugar.

If you are ramping up the main mash to mashout, why are you adding 82c sparge water? What temp does that settle at? To me since your grain bed is already at mashout temps, the sparge water should only need to be at the same temp.

QldKev


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## Online Brewing Supplies (14/3/13)

I stir once at mash/dough in thats it, I can get 82% effic but dumb it down to 76% so I dont get below 1.010 onmy last runnings.
Nev


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## Acasta (14/3/13)

I would not recommend stirring truman, If you do you will disturb the grain bed. I only stir, as others have said, when I add the sparge water then rest again before recirc begins.
As for the eff. I get about 85-87% MASH efficiency (which is the important one imo) with a regular 55/65/78 step mash, one thing I noticed is your mashout is 75 so you may want to increase that a little. Not too much as you risk tannin extraction.

I think one of the other big impacts of mash efficiency (measured as 'into the boiler') along with crush and sparge as QldKev said is the mash tun loss! My mash tun pickup under my false bottom is extremely close to the bottom of the tun, I let it pump until I hear the suction from in the tun, then I take off my hose at the MT outlet and get all the liquid out of the herms line (by blowing on the other end of the hose) and pour that into the kettle through a sieve. That has reduced my loss alot and I believe helps for a good mash efficiency.


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## Bada Bing Brewery (14/3/13)

Gryphon Brewing said:


> I stir once at mash/dough in thats it, I can get 82% effic but dumb it down to 76% so I dont get below 1.010 onmy last runnings.
> Nev


I'm with him ....
I always get between 70 & 75%, fly sparge - never stirring.......
Cheers
BBB


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## mxd (14/3/13)

I batch and stir at Dough-in and between each sparge,

I have thought (I like to play and something to do) about putting a "stirrer" in the tun to stir for the full mash


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## browndog (14/3/13)

> @browndog... I also stir between at the start of the first and second sparge? How long do you sparge for each time? 10 mins?


Right, I neglected to see that. If by sparge, you mean recirculate, then as soon as the wort is running clear it's into the kettle, no more than a couple of mins stirring and 5 mins or less of recirculating.


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## Truman42 (14/3/13)

> I think a big % of the efficiency comes from the crush and the sparge. Crush needs to be fine enough so not too much sugar is caught in the sparge, and the sparge needs a good stir to mix into suspension all the sugar.
> 
> If you are ramping up the main mash to mashout, why are you adding 82c sparge water? What temp does that settle at? To me since your grain bed is already at mashout temps, the sparge water should only need to be at the same temp.



Now that I have my own grain mill I can buy grains uncrushed and see how I go crushing my own instead of relying on the crush from the LHBS.

I add 82C sparge water as I lose a bit by the time I stir it etc. Its usually around 78C once I begin recirculation.

@ Acasta..My mash tun pick up is at the very bottom of my keg. (The keg is on legs so the outlet comes out under that so dead space in the mash tun is minimal. I do blow out the lines but dont usually collect the wort so might do that from now on.

How exactly do you measure mash efficiency into the kettle? Brewmate only has a brewhouse efficiency calculator. If I put in my figures say from my last recipe of SOB gravity 1.040 and volume of 37.5 litres it gives me 84%. Does that sound right? If so maybe Im doing better than I thought.


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## Truman42 (14/3/13)

browndog said:


> Right, I neglected to see that. If by sparge, you mean recirculate, then as soon as the wort is running clear it's into the kettle, no more than a couple of mins stirring and 5 mins or less of recirculating.


Ok so waiting 10 mins is pointless? Great, Always trying to knock off a few extra minutes of my brew day. Will try that next time, cheers.


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## JDW81 (14/3/13)

Truman said:


> How exactly do you measure mash efficiency into the kettle? Brewmate only has a brewhouse efficiency calculator. If I put in my figures say from my last recipe of SOB gravity 1.040 and volume of 37.5 litres it gives me 84%. Does that sound right? If so maybe Im doing better than I thought.


It depends on the grain bill, mash temp and length and the type of sparge you use, but assuming you have got your ducks in a row it doesn't sound like 84% is too far off. I get about 75% mash efficiency with single infusion and double batch sparge, but with HERMS you should do better than me.

I don't calculate my mash efficiency though, I let beer smith do it for me. So long as it is a consistent 70-75% I'm a happy brewer. Got more important things to worry about than chasing a few extra points of efficiency for the sake of it.

JD


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## Truman42 (15/3/13)

So using beersmith I imported my last recipe and input the figures into the efficiency table and I still get 84% mash efficiency. So I can assume that my brewhouse efficiency is dropping possibly because my settings such as trub loss, evaporation rates etc need more tweaking.
i did notice that my usual evap rate of 15% is off as Im not losing that much and have since reset this to 12 % based on my last brew. But Ive also noticed that for my last few brews Ive always been around 5 points under at EOB.
Could this be because my evap loss was set too high?


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## QldKev (15/3/13)

Truman said:


> So using beersmith I imported my last recipe and input the figures into the efficiency table and I still get 84% mash efficiency. So I can assume that my brewhouse efficiency is dropping possibly because my settings such as trub loss, evaporation rates etc need more tweaking.
> i did notice that my usual evap rate of 15% is off as Im not losing that much and have since reset this to 12 % based on my last brew. But Ive also noticed that for my last few brews Ive always been around 5 points under at EOB.
> Could this be because my evap loss was set too high?



In Beersmith it has a field where you can enter the volume, so even if you didn't get the desired vols it should equal the same efficiency.


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## Wolfman (15/3/13)

I have also been struggling with efficiency. I was also wondering if it had to do with the crush. Though id experiment on the last brew day. So the first brew looked like the kernels were not crushed enough. About 65% on that brew. The second brew I though I would tighten the gap and double mill. What a mistake. Two stuck mashes! Pretty sure ill find out that hot side airation is real with this batch. Was a major **** up of a day which I won't fully go into. 

So, my question is What is the best gape distance on your mill for a Herms brewery?


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## benno1973 (15/3/13)

I'm with Nev and BBB. I stir at dough-in and don't touch it after that. I've only done recirc on my last few brews, but recirc or not, I hit around 80% efficiency.


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## Online Brewing Supplies (15/3/13)

Wolfman said:


> I have also been struggling with efficiency. I was also wondering if it had to do with the crush. Though id experiment on the last brew day. So the first brew looked like the kernels were not crushed enough. About 65% on that brew. The second brew I though I would tighten the gap and double mill. What a mistake. Two stuck mashes! Pretty sure ill find out that hot side airation is real with this batch. Was a major **** up of a day which I won't fully go into.
> 
> So, my question is What is the best gape distance on your mill for a Herms brewery?


Cant give you a size but if you crush so the grain is still 50% intact and when you rub it between your hands it falls apart you are pretty much on track.
Efficiency will grow as the flow thru the grain beds increases.
Nev


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## QldKev (15/3/13)

I may give the next brew a no stir approach and see how the efficiency compares. Maybe I'm just wasting my time waiting for it to clear up after stirring it.


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## browndog (15/3/13)

I've been trying to get my efficiency up on my new rig and noticed that my crush (due to lack of maintenance on my home made mill) had a lot of whole grains in it. While the grains did break up when rubbed, I decided to run it through the mill a second time and see how that effected efficiency. After the second time through there were no more whole grains to be seen and I was a bit worried I was going to be in for a stuck sparge. So the result, no difference in efficiency at all.


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## Wolfman (15/3/13)

Gryphon Brewing said:


> Cant give you a size but if you crush so the grain is still 50% intact and when you rub it between your hands it falls apart you are pretty much on track.
> Efficiency will grow as the flow thru the grain beds increases.
> Nev


Cheers mate will adjust before next brew day.




QldKev said:


> I may give the next brew a no stir approach and see how the efficiency compares. Maybe I'm just wasting my time waiting for it to clear up after stirring it.


I was getting good efficiency when fly sparging and not stiring the mash. Gone back to batch sparging, little less time consuming, and maybe this is where some of the hit has come from? Next time will try with a spilt sparge and a no stir with a 10 min recirc at 75c on both sparges.

Kev i'd be interested to hear the results if you brew before me next.


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## Parks (15/3/13)

browndog said:


> I've been trying to get my efficiency up on my new rig and noticed that my crush (due to lack of maintenance on my home made mill) had a lot of whole grains in it. While the grains did break up when rubbed, I decided to run it through the mill a second time and see how that effected efficiency. After the second time through there were no more whole grains to be seen and I was a bit worried I was going to be in for a stuck sparge. So the result, no difference in efficiency at all.


I've found the crush to make a big difference in my efficiency. My last few brews have been back down under 70% (from close to 80%) and I realised that I hadn't checked the gap on mill...

It had slipped from 0.9 to 1.3mm.

The grain still looked crushed enough, but obviously that in combination with my system made a big difference.


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## mckenry (15/3/13)

Just to add my 2c
Truman,
Can you underlet?
I also only sir at mash in, never again.
When I do my sparge, I underlet. This raises the grain bed again, I recirc for a few minutes til I see clear wort into the wort return dish, then off to the kettle.
Underletting is great. My eff is just shy of 90 and never a stuck sparge and the clarity into the kettle is great. Not that that is the be all and end all.

I tried stirring during the mash, at ramps etc like you do / propose, but all that changed was I had to recirc for much longer to get clear wort.

I run my pump the entire time, so the wort is going through the grain bed for a long time. both from top to bottom, then bottom to top (sparge) then top to bottom (recirc) then off to kettle.

This keeps my grain bed set, but not compact. I also mash in at 3L/kg


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## dago001 (15/3/13)

Wouldnt a refrac test prior to stirring and after stirring/recirc tell you if there is a noticeable gain to be had. I have tried stirring the mash at mash out, as I thought that it may help increase efficiency. I never noticed any difference, so didnt bother after that. Not inclined to bother again either. I mash fairly thin around 3.5/1 depending on the brew size, and always find that at the end of the sparge, I am getting a 1010ish reading, so I figure I have extracted all that I can. There may be entrapped sugars in the mash, but as I am getting an efficiency of 75%, they can stay in the mash. I have never really bothered trying to increase my efficiency, as I know what my system will output consistently. You may never reach 80% efficiency with your system.
I am more concerned about producing a beer that is not only of good quality, but will give me the exact same result every time I brew. Too much emphasis on the maths. Spend more time refining your system and techniques.
I built a herms system to simplify my brewing, granted the system is more complicated, but the actual procedure is pretty straigthforward. If I wanted to stir the mash more than once, I would go back to BIAB. No need to overcomplicate a simple system.
2c
Cheers
LagerBomb


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## Truman42 (15/3/13)

mckenry said:


> Just to add my 2c
> Truman,
> Can you underlet?
> I also only sir at mash in, never again.
> ...


Yes I could underlet as my HLT is higher than my MLT so gravity should allow me to run the sparge water down and into the MLT outlet tap at the botom of the mash tun. Will certainly be giving this a go the next time to see if it improves my efficiency.


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## GalBrew (15/3/13)

mckenry said:


> Just to add my 2c
> Truman,
> Can you underlet?


Out of curiosity (not the most experienced with sparging as I BIAB) is underletting an efficient way to rinse the grains? I am assuming that is a batch sparge? Does it effectively rinse the whole grain bed or do you get an inverse channelling thing going on?


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## Wolfman (15/3/13)

mckenry said:


> Just to add my 2c
> Truman,
> Can you underlet?
> I also only sir at mash in, never again.
> ...


Does this upset/change the grain bed? Do you add all the sparge water at once? How are you recircing your mash?

I can underlet as I have a LBP on my HLT, so will also try this. I think the way the wort is returned to the mash tun may also hold the key. I have tried a laidle with the hose conected, very complicated. Now just sit the silicon hose on top and this creates a whirlpool effect.

Whats peoples thoughts on this?


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## mckenry (15/3/13)

GalBrew said:


> Out of curiosity (not the most experienced with sparging as I BIAB) is underletting an efficient way to rinse the grains? I am assuming that is a batch sparge? Does it effectively rinse the whole grain bed or do you get an inverse channelling thing going on?


Yes mate. Channelling occurs when the liquid runs in one direction (down, with gravity as it will find the path of least resistance) all the time. So underletting means you cant channel the grain bed as gravity forces the liquid to flatten out as it rises, therefore soaking the entire grain bed, rinsing all the grain.


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## mckenry (15/3/13)

Wolfman said:


> Does this upset/change the grain bed? Do you add all the sparge water at once? How are you recircing your mash?
> 
> I can underlet as I have a LBP on my HLT, so will also try this. I think the way the wort is returned to the mash tun may also hold the key. I have tried a laidle with the hose conected, very complicated. Now just sit the silicon hose on top and this creates a whirlpool effect.
> 
> Whats peoples thoughts on this?


Quite the opposite of upsetting it. The grain is gently lifted with the liquid pouring in from underneath which 'loosens' it without disturbing it.
No, I sparge in two even goes, but only due to the size of my MT. Its 50L and I need 72L preboil
I have a HERMS so constantly recirculating, with a beerbelly return dish. I set the dish so the top of it is at the top of the grain. Wort comes into the dish then flows out over the flat grain bed and distributes evenly.
whirlpool is not ideal, you want it slower than that, but its probably better than a waterfall in the one spot as thats the kind of thing that leads to channelling. Get a wort return dish or go ghetto and just punch heaps of holes into a big coffee tin lid or similar.


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## dago001 (16/3/13)

Thought I would revisit the stirring of the mash routine and take a few refrac readings at the same time. At the end of the mash out I took a refrac reading which was 1069, as I expected it to be. Gave the mash a good stir and let it settle for a minute then took another refrac reading. Initial reading jumped to 1072. Let it recirc for 5 minutes took another reading - 1070. It took about 10 minutes before I was happy with the clarity of the wort, took another reading 1069. Not too sure what this proves and where the initial jump in gravity came from, but the final result for me was 46 litres into the boil at 1048, exactly what my recipe said it would be, at the efficiency it said it would be.
So the conclusion for me is that I have wasted about 15 minutes time to prove what i already knew. I would be interested if anybody else has came up with a different result to me.
Theres nothing wrong with chasing better efficiency, but for me, Im happy not to bother with stirring again. I know what my system is capable of, but that changes whenever I do a modification. I have just purchased a new mill, replacing my much loved home made mill. I will be interested to see what that does to my brewing results
Cheers
LagerBomb


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## Truman42 (18/3/13)

Interesting conclusion lagerbomb. Your tests would conclude that stirring seems to be a waste of time.

@mcKenry..So when you underlet do you also bother to give the mash a stir after youve added your sparge water? Or do you just underlet your sparge water, recirc for a few minutes until the wort runs clear then transfer to the kettle and repeat for the 2nd batch sparge?


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## Screwtop (18/3/13)

Once we reach a good/happy point in our brewing process, most brewers then begin to look at ways to shave off some time or make the day easier while maintaining efficiency, so our processes change over time.

Thought I might relate some changes to my process.

Underletting:
Found that due to temp losses involved (HLT and lots of other SS stuff) I needed to underlet at a high strike temp to achieve sacch rest temp. The high conversion rate of some malts meant the resulting wort was more dextrinous (complex sugars) than planned and resulted in lower attenuation. So I moved to underletting for a Protien Rest which meant lower strike temp and attenuation went back up.

To save time: Used to wait until total brewing liquor in HLT had reached strike temp - Now strike water is underlet to the EMPTY MLT once the temp has reached about 50C, the remainder continues to heat to Mash Out temp in the HLT. Recirculation is begun using the HERMS HEX and in about 15 min strike water/MLT and all plumbing etc has attemporated at mash temp (Sacch Rest Temp, dropped Protien Rest). About half of the grist is added and given a gentle stir to mix, remainder is added and again a few turns using the mash paddle, temp drops 5 or 6 degrees. Takes about 10 min of recirculation for the mash to be back at the Sacch Rest temp and the mash timer is set.

Sparging: Have always preferred fly/continuous sparge as I'm lazy. Preboil volumes had never been an issue and were always spot on, however preboil gravity was usually a little above target. For each successive batch the brewhouse eff% would be increased in Beersmith, but preboil gravity would always be a little above target until I got to 92%.

By then my beers were suffering from astringency. PH is adjusted using brewing salts and tests showed sparge PH was not the cause. Sparge temp was dropped to 76C but astringency remained. Thought about dropping back the eff% in beersmith, but this would screw up volumes and gravity targets. Emailed some other brewers for their opinions, some advised to reduce sparge volume which made sense but how could I do that and maintain volumes?? Take some of your sparge water out prior to sparging and add it to the kettle was the answer. Tried removing 6 litres (double batch) of sparge water prior to sparging and adding it to the kettle, surprise - preboil volume and gravity was spot on, wow! even though 6 litres of water has not travelled through the grist. Astringency was all but gone from this batch. For the most recent batch 10 litres of sparge water was dropped straight to the kettle before sparge began. Again gravities and targets were spot on, no astringency detectable and maltiness has returned. Obviously the extra sparge water was removing nothing more from the grist other than tannins from the husks. Obviously sugars were fully rinsed from the grist as preboil gravity has been maintained.

Truman, I believe your eff% should be higher as others have said, maybe it's in the calculation. Like others I have not found a great difference in grind gap settings, only a few foints in eff%.

Hope this helps others.

Screwy


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## mckenry (18/3/13)

Truman said:


> Interesting conclusion lagerbomb. Your tests would conclude that stirring seems to be a waste of time.
> 
> @mcKenry..So when you underlet do you also bother to give the mash a stir after youve added your sparge water? Or do you just underlet your sparge water, recirc for a few minutes until the wort runs clear then transfer to the kettle and repeat for the 2nd batch sparge?


No stirring. I just stir at mash in, then thats it.


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