# Underletting-pros & Cons



## mikem108 (3/10/06)

Have made my first brew using the underletting method and all went OK. 
What are the benefits or downsides of this method?


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## Bobby (3/10/06)

i havent noticed any downsides, i always underlet and never have problems with doughballs.


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## goatherder (3/10/06)

underletting works for me too, no doughballs. I do run relatively thin mashes (3:1) though.

The biggest advantage for me is that I can attach the hose to the MLT tap instead of just dangling it into tun. This keeps everything steady whilst I'm messing about turning HLT taps and watching the water level with the dipstick. It's more a "one less thing to watch" reason than anything.

are we going to have another crack at the water to grain vs grain to water argument?


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## Ross (3/10/06)

How long does it take to underlet a reasonable sized batch in a cylindrical mash tun?

cheers Ross


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## Sammus (3/10/06)

forgive the stupid question but whats underletting?
is it just kinda like throwing you strike water in backwards through the outlet?


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## goatherder (3/10/06)

> How long does it take to underlet a reasonable sized batch in a cylindrical mash tun?
> 
> cheers Ross



For me, roughly the same as dumping the water on top. I only do smallish batches (23l) and I feed the water in under gravity from the HLT. It takes about 2-3 minutes to underlet my mash-in water.




> forgive the stupid question but whats underletting?
> is it just kinda like throwing you strike water in backwards through the outlet?



Yep, that's exactly it.


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## Kai (3/10/06)

Ross said:


> How long does it take to underlet a reasonable sized batch in a cylindrical mash tun?
> 
> cheers Ross



Depends on the fittings and tubing you're using. Does not take me more than a few minutes, but then when I was not underletting I was running through a tube anyway to help prevent splashing and temp loss.


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## Tony (3/10/06)

My mash underlets as fast as a march pump can pump 30 liters through 1/2 inch line into 10kg of grain.

about 2 minuites then just stir and bake for 1 hr at 66 deg......... oh you know the rest


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## big d (3/10/06)

Dicko put me onto underletting and ive done it this way ever since.Time is about the same top or bottom.Best benifits i can see are no dough balls and an even steady upward flow of water(no channeling).Looks good seeing the colour come through as the water rises and mixes with the grains.Also i quess there is less stirring of the grain to remove any suspect dough balls/dry spots.

Cheers
Big D


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## Anachi (3/10/06)

Only ever had a problem with underletting when my mate shook the dry grain up in the tun. Must have compacted it down as the water refused to flow up through the grain :S

Otherwise i can't think of why you would do it any other way ;D


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## razz (3/10/06)

Mikem108. Only one reason why I don't underlet, I flood my mash tun the night before and then, in the morning, recirc through a herms to hit the required dough in temp. It's no big deal for me, it's only 1-2 minutes stirring to make sure the dough balls are broken up anyway. And I'm doing double batches.


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## Ross (3/10/06)

I guess I'll give underletting a go when i install a sight glass on the tun so i can see how much i've added. Until then i'll continue to just pour the grain from a height straight onto the water - mines all poured/mixed with no dough balls within 30 seconds. Seems preferable to me rather than passing hot water through the lower grains for several minutes, but it would appear it doesn't cause too many problems for those doing it.

cheers Ross


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## Kai (3/10/06)

The grain's hitting hot water whether the water goes in the bottom or the top. Even if you have a shorter duration of hot temps by your method, you're exposing more of the grain to hot water.

Ultimately I do not think it matters either way in terms of enzyme loss.


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## Bobby (3/10/06)

a sight glass on the tun? isnt that asking to be clogged by bits of grain?
i use a dipstick in my hlt and shut off the vlave when i get to teh desired volume. ideally you would have a sight glass on the hlt.


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## Ross (3/10/06)

Bobby said:


> a sight glass on the tun? isnt that asking to be clogged by bits of grain?
> i use a dipstick in my hlt and shut off the vlave when i get to teh desired volume. ideally you would have a sight glass on the hlt.



I was refering to the hlt - hot liqour tun, not the mash tun B) 

cheers Ross


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## JasonY (3/10/06)

Gave this a shot on the weekend for the first time, worked like a charm. Just pumped in the right amount of hot water, quick stir and it was done. Much less stirring than my previous way of adding the water to grain and stirring madly.

Can't see any disadvantages?


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## Tony (4/10/06)

definatly go for it ross!!!!

It is much easier and looks great as the water comes up through the grain 

I was suspicions to start with as well but once i did it once i would never do it another way ever again.

Its one of those things you have to do to apreciate....... you go......... ooooohhhhhhh whay didnt i do that sooner 

cheers


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## Aussie Claret (4/10/06)

Whilst being relatviely new to the AG seen I have under let everytime, after a good local AG'er recommended this to be the way to go.

Have never changed and never have any dough balling, it only takes a couple of minutes and I work out how much water I've added by the use of a sight glass on the HLT.

Now the local AG'er seemes to think it might be worth a try, was I the Guinea Pig here Rosco? LOL

AC


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## Jez (4/10/06)

I've underlet with each of my 4 AG brews as well. Very quick procedure & never any doughballs.

Also it's fun to listen to the grain crackling away as the water rises in your mash tun. Reminds me of when you pour the milk on rice bubbles.

Jez


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## Ross (4/10/06)

Aussie Claret said:


> was I the Guinea Pig here Rosco? LOL
> 
> AC



Hey mate, you can't expect PistolPatch to take 'em all for the boys  

As I said, it'll probably be the way I go, once I get a sight glass fitted... certainly clean & simple...

cheers Ross


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## doglet (4/10/06)

I use a dipstick in the HLT rather than a sight glass. Just as easy.

Can't find it at the moment baut there was a big discussion a while ago re: the pros an cons with enzyme breakdown etc. The general consensus I remember was that it isn't a big enough problem to worry about - just have to hit the strike temp and away you go!


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## Ross (4/10/06)

doglet said:


> I use a dipstick in the HLT rather than a sight glass. Just as easy.



Not when your HLT is above head height - unless you like standing on buckets B) Will get there one day...  

cheers Ross


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## doglet (4/10/06)

Ross said:


> doglet said:
> 
> 
> > I use a dipstick in the HLT rather than a sight glass. Just as easy.
> ...


Ah yeah - Single tier here. What was that saying about real brewers and March Pumps!! hehehe h34r:


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## Tony (4/10/06)

you beat me to it doglet 

hehehehe


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## Ross (4/10/06)

doglet said:


> Ah yeah - Single tier here. What was that saying about real brewers and March Pumps!! hehehe h34r:



.......That's because I'm an unreal brewer


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## Trough Lolly (4/10/06)

Underletting the mash = substantially reduced mash oxidation...

Cheers,
TL


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## dicko (4/10/06)

As Big D said earlier, I underlet and would not go back to the other way.
I have a 50 litre HLT and I add EXACTLY the required amount of water only for the mash. I then heat this to the infusion temp and drain the lot to the mash tun by underletting.
While the mash is happening I add the remainder of the water required to complete the brew to the HLT and bring it to the boil.
When the mash is completed I infuse the correct amount of boiling water into the mash to raise the temp to mash out (74 to 76 deg) I then top up th HLT with cold water by the same amount as I infused for mash out.
This generally gives me the balance of water of around 76 deg for the sparge.
I know this may be a little OT but it seems to work for me and it saves a lot of measuring.

Cheers


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## Lindsay Dive (5/10/06)

Having read this thread, I thought I would give underletting a go. After watching what was happening I was thinking of the grain at the bottom of the mash tun getting belted continuously for about ten minutes with water well above the ideal temperature for them.
Definitely no dough balls though and much less grain dust in the air.
I would like to know what is happening to the grain at the bottom of the tun before you stir the mash?

Regards,
Lindsay.


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## Duff (5/10/06)

I had a chat to GMK about this last Monday. Biggest problem I have is that when I underlet the whole grain bed rises as the strike water does not seem to filter through. The only one I've had real success with is my Weizen a couple of weeks ago. I crush fairly fine and it must be the problem as I literally have to stand there and push the grain bed down so it doesn't come out the top of the mash tun.

Any suggestions?


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## Ross (5/10/06)

Lindsay Dive said:


> Having read this thread, I thought I would give underletting a go. After watching what was happening I was thinking of the grain at the bottom of the mash tun getting belted continuously for about ten minutes with water well above the ideal temperature for them.
> Definitely no dough balls though and much less grain dust in the air.
> I would like to know what is happening to the grain at the bottom of the tun before you stir the mash?
> 
> ...



lindsay - are you saying that it took 10 minutes for you to underlet? I would not be happy if it takes this long, hence my earlier question - a couple of minutes fine, but i reckon this may be pushing it. 

With Duff's fine crush problem, it looks like quality of cracking may be an issue here...

Cheers Ross


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## warrenlw63 (5/10/06)

Trough Lolly said:


> Underletting the mash = substantially reduced mash oxidation...
> 
> Cheers,
> TL



Sorry to drift slightly OT here.

I don't underlet ATM. As much as I like the sound of it I have reservations about the strike water coming form my HLT being "exactly" to strike temp. At least if I add the water first then dump in the mash I know the strike water is going to be precise. If and when I find a way of getting exact strike water temps into the tun then I will most definitely underlet. The idea of no doughballs appeals to me.  

OTOH if you have concerns about mash oxidisation (personally I think the worry is minimal) then what I've been doing lately is adding 1/4 of a crushed Campden tablet to the mash liquor. Results could be purely in my head but I'm fairly certain that my beers seem to be keeping far more stable in the keg since I've been doing it. 

Could be purely a placebo but others seem to swear by it. :unsure: 

Warren -


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## Lindsay Dive (5/10/06)

Ross,

I said about ten minutes. Ill time it next time I'm game enough.
I can vaguely remember somebody saying something about Beta Amylase doing some damage to the grains very quickly if the strike water is too hot.

Regards,
Lindsay.


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## Ross (5/10/06)

Lindsay Dive said:


> Ross,
> 
> I said about ten minutes. Ill time it next time I'm game enough.
> I can vaguely remember somebody saying something about Beta Amylase doing some damage to the grains very quickly if the strike water is too hot.
> ...



This is my main concern, especially when using malts like Galaxy that convert so quickly.
I tip the grains into the water from a height, so they break the surface & they are all in with 5 seconds - occaisionally there's a little left on top, but takes less than half a minute to stir these in, with no dough balls - So for me i really can't see any advantage, as I have to tip the grains in either way & there's the potential of over heating the grains if it takes too long - I'm getting 85% efficiency batch sparging & getting the attenuation i want generally spot on. So reluctant to add a process that may throw things out a bit...
Not knocking the process as it obviously works well for many - as I said, I just can't see any advantages within my set-up.

Cheers Ross


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## Steve (5/10/06)

With underletting you wouldnt get those annoying hot geyser type bursting bubbles like when you add the strike water to the grain....they always get me :angry: 
Cheers
Steve


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## Ash in Perth (5/10/06)

The reason i do not underlet is, because i have a SS keg mash tun with a huge thermal mass, the hot liquor needs to be going in at about 78 Degrees. As it works its way up through the grain, the bottom 1/3 or so of the malt is going to get to mash out temperatures before re-circulation can begin.

This would not be as much of a problem with a plastic style mash tun.

What i do is get the water up to temp (about 70) by re-circulating through the HLT. this gives me time to adjust the pH and weigh and mill my malts. Then i throw in the malt into the top with stirring. Works well for me but depends on yours brewery.


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