Edge or central pick up in a mash tun?

[guypettigrew]

Since buying a lovely shiny new mash tun from Hop and Grape my efficiency has dropped! It has a false bottom and, as you can see, draws off from underneath the false bottom at one side.

The tun is excellent. It keeps the temperature extremely well and I've fitted a Blichman autosparge to it, which makes managing the run off really easy.

The drop in efficiency is a few percentage points. Using an insulated cool box with a 'D' manifold I was getting efficiency in the mid to high 70%s. Now it's in the low 70%s. I've done a good fifteen brews in the new tun, so it's giving consistent results.

It's not really a problem. A bit more grain sorts it out. But it would be nice to up the efficiency to the high 70%s again.

I'm wondering if the side run off may be a contributing factor. The 'D' manifold, of course, pulled wort from all the way round the old tun.

So, buying one of these central pick up false bottoms from the Malt Miller crossed my mind.

Does anyone have any idea whether a central pick up is likely to increase the efficiency?

Guy

[orlando]

Much more likely to be the sparge method. Try slowing it down. I used to fly sparge and relied on gravity to drive the sparge arm, problem was that you had to deliver sparge liquour at a high rate to keep it spinning that meant it was reducing its efficiency. Fly sparging is an influence of big brewers and one of those influnces that is probably overkill at our scale. Are you pumping your liquour or relying on gravity. I have simplified my sparge method and adopted the Electric Brewery method and seen much improvement. You mention the auto sparge, which I've not used, but assume can be adjusted to sparge slower? Temperature of sparge water is also an area to look at.

[guypettigrew]

The sparge rate is about 1/2 litre a minute. It takes about an hour or more to collect about 32 litres of wort for boiling.

The autosparge keeps a constant height of liquor on the grain. Some pictures from t'interweb here.

The liquor from the HLT is slowly pumped to the autosparge which, as it has a stainless steel float ball valve, cuts the flow off when the liquid level gets to the set point.

During sparging the top of the grain bed stays at about 70C.

My previous method used a spinny sparge arm over the grain in cool box, gravity fed. Much less technically impressive but, somehow, more efficient.

Guy

[orlando]

The sparge rate is about 1/2 litre a minute. It takes about an hour or more to collect about 32 litres of wort for boiling.

The autosparge keeps a constant height of liquor on the grain. Some pictures from t'interweb here.

The liquor from the HLT is slowly pumped to the autosparge which, as it has a stainless steel float ball valve, cuts the flow off when the liquid level gets to the set point.

During sparging the top of the grain bed stays at about 70C.

My previous method used a spinny sparge arm over the grain in cool box, gravity fed. Much less technically impressive but, somehow, more efficient.

Guy

Well that all sounds about perfect, the only thing I would comment on is raising the sparge temperature so the grain bed is closer to 75 or higher but less than 80.

[guypettigrew]

Thanks Orlando

Raising the temperature of the sparge liquor a few degree would be easy enough, I'll give it a go.

But you reckon a central pick up in the mash tune wouldn't make any difference to the efficiency?

Guy

[orlando]

Thanks Orlando

Raising the temperature of the sparge liquor a few degree would be easy enough, I'll give it a go.

But you reckon a central pick up in the mash tune wouldn't make any difference to the efficiency?

Guy

To be honest Guy, I have only ever used a false bottom, one domed the other full width and I don't believe either is better than the other. There are a number of factors that go into efficiency so it is not a simple mater to pinpoint one thing. Take mash pH for example, get this wrong and it won't matter what the geometry or make up of your Tun is. If you have a decent enough amount of liquour covering the grain bed, making sure the goods float and don't compact and this is at the right temperature, you should wash out the sugars pretty efficiently whatever you have, but there is a lot more too it than just this. Us Brewers can be a bit like golfers, "if I can only get the right club/bit of kit, my problems are over".

[guypettigrew]

If you have a decent enough amount of liquour covering the grain bed, making sure the goods float and don't compact and this is at the right temperature, you should wash out the sugars pretty efficiently whatever you have, but there is a lot more too it than just this. Us Brewers can be a bit like golfers, "if I can only get the right club/bit of kit, my problems are over".

Well, that's me told!

Seriously, though. There must be a technical/equipment reason why my mash efficiency has dropped. The pH has remained the same (about 5.3), the mash temperature has remained the same and my liquor treatment hasn't altered.

The grain still comes from the Malt Miller and the electricity still comes from EDF!

The change is in the kit. Which is why I wondered if a domed centre pick up false bottom in the mash tun might more effectively pull all the sugars out of the grain.

Guy

[BenB]

I know this was discussed on Brew Strong recently (I think it was the latest Blichmann Q+A) and they suggested it would make absolutely no difference until you get to mash tuns metres in diameter. Whether this is based upon empirical research or gut feeling was not elucidated

[orlando]

If you have a decent enough amount of liquour covering the grain bed, making sure the goods float and don't compact and this is at the right temperature, you should wash out the sugars pretty efficiently whatever you have, but there is a lot more too it than just this. Us Brewers can be a bit like golfers, "if I can only get the right club/bit of kit, my problems are over".

Well, that's me told!

Seriously, though. There must be a technical/equipment reason why my mash efficiency has dropped. The pH has remained the same (about 5.3), the mash temperature has remained the same and my liquor treatment hasn't altered.

The grain still comes from the Malt Miller and the electricity still comes from EDF!

The change is in the kit. Which is why I wondered if a domed centre pick up false bottom in the mash tun might more effectively pull all the sugars out of the grain.

Guy

Apologies, didn't mean to lecture but I really don't think the kit is the issue. Keep trying different things, do you use software at all? Have you changed your malt from one batch to another? There are so many different parameters, it just isn't kit as much as we all like to believe.

[Mr. Dripping]

I think a side pick up may affect efficiency.....hopefully I can explain this properly.
Fly sparging is a serial dilution of the wort. If you are pulling from the side of the tun I think there is the possibility that there may be some channelling of the sparge liquor down the route of least resistance i.e towards and through the tap.....you would after a time have the wort furthest away from the tap at a (much) higher gravity than the wort nearest the tap. I hope I've explained my thinking correctly.

Maybe try a batch sparge and compare the efficiency?

[Fastline]

Has the change in kit significantly altered the grain bed depth?

Id say the raised temp thing should help 70 sounds a little low from what I understand, maybe coupled with a deeper grain bed you are just not washing all the potential sugars as easily as before.

Does Wort seem clearer, I.e also getting a better filter through deeper grain bed

If grain depth is same or thinner blows that out of the water

[guypettigrew]

Hi Fastline

Grain bed depth is probably about the same with the new kit, perhaps a bit deeper. It filters better than the cool box set up. The wort gets clear much more quickly.

I might go back to the old cool box mash tun for a brew and see what happens. Or I might buy the domed central pick up base from the Malt Miller to see if it improves the efficiency.

Something's made a difference, that's for sure.

Guy

[Fastline]

The picture doesnt show the false bottom too well, is it just a large fully perforated disc?

What size holes / spacing

[guypettigrew]

It's a large fully perforated disc. I think the holes are 3/32" on 5/32" centres.

Should be fine, but my instinct still suggests a centre drain would work best.

Guy

[Cheesey]

Hi Guy,

I have the same set up from Hop and Grape (I live in Darlo !) , and I have only used this gear, so I have nothing to compare it with. But when considering what to get I read John Palmers How to Brew , he mentions false bottoms are near 100% efficent when fly sparging, I don't think the side exit is an issue. he goes in to a lot of fluid mechanics which I didn't understand!.

However I gave up fly sparging as found it too slow and troublesome, as the arm didn't turn at the speed I wanted. I have messed around with different batch sparge methods , and because the MT is so well insulated I find if I leave it at 66'C for 90 to 120 mins i'm only loosing a degree, then do two batch sparges of 10 mins I am getting over 80%, the last one near 90%!.