Fly Sparging question

[kenack]

I've been doing 12 gallon batches for 7 years using fly sparging from 10 gallon HTL at 180 degrees pumped into mashtun while slowly draining wort into kettle. My question is this, how does the sparge water ever get the grain bed to 168? As I slowly sparge it sets on top of 154 degree water and combines to be something higher than 154 but I've never seen my thermometer read 168! So, am I achieving the necessary mashout temps?

I'm thinking of changing to a two batch sparge and see the difference. Also, does anyone use a RIMs tube to recirculate the batch sparge water at 168?

Thanks,

Ken

 

[processhead]

I see something similar with my system.
I have observed a sparge water temperature drop between my HLT and MLT during fly sparging that I attribute to the low flow rate and heat losses from the uninsulated tubing I am using.
I compensate for the loss by raising the temperature of my sparge water in the HLT.
Do you think this is affecting your extraction efficiency?

 

[kenack]

Yes I do, that's why I'm contemplating batch sparging.

Ken

 

[doug293cz]

Sparge water temp isn't going to affect your extraction (mash) efficiency. Mash efficiency is equal to conversion efficiency times lauter efficiency. Some people who do a mash out by heating the mash prior to sparging see an increase in conversion efficiency, but only if the conversion wasn't complete at the end of the designated mash time. This is due to "supercharging" the rate of conversion due to the higher temp, and the longer time allows more conversion, until the enzymes are completely denatured. So, naturally if you have 100% conversion at or before the end of the mash, the mash out cannot drive the conversion past 100%.

However, if you try to achieve a mash out using high temp fly sparge water, the enzymes will be rinsed away locally before the local mash temp reaches 168°F - 170°F.

Brew on

 

[Shwagger]

So if I reach full conversion during the mash, what does using a certain temperature sparge water do? If all it's doing is rinsing and not converting.

I guess helping reach boil sooner because it's already hot. But how critical is that 168 degree sparge temperature?

 

[pricelessbrewing]

So if I reach full conversion during the mash, what does using a certain temperature sparge water do? If all it's doing is rinsing and not converting.

I guess helping reach boil sooner because it's already hot. But how critical is that 168 degree sparge temperature?

IMO Nothing.

There is the argument that it makes lautering faster/easier. I'm not sold on it though, as I have not seen data to support this theory. We know that viscosity of sugar solutions do not increase to a substantial amount, however beta glucans and proteins may become denatured and decrease wort viscosity. I'm not of that opinion though

 

[65C]

this is something I've still not worked out - I've got the strike part of the mash understood fine - but then I'm doing two batch sparges at 77C (which takes it to <70C grain temp at that point) but I don't know why I'm using 77C but that's the number I keep reading:

1. what temp should grain be for the batch sparge? and why?

2. when I do the batch how long do I leave it before drawing the wort off?

I don't think I've got a problem in this area - but I don't understand why I'm doing what I'm doing

any help appreciated

 

[day_trippr]

77°C = 170°F, which is the generally recommended mash-out temperature (whether it matters or not).
And if it matters it's more pertinent to fly sparging which is a much more protracted process compared to batch sparging.
Eg: it takes me just under an hour at 1 quart per minute to complete a fly sparge for a 10 gallon batch with the usual 13 gallons pre-boil volume.
If I did a single batch sparge it'd take roughly 20 minutes total.

My practice for batch sparges was to dump in the sparge liquor, give the MLT a good stir, let it settle for 10 minutes, then drain it rather rapidly.
Some folks cut the 10 minutes down to almost nothing...

Cheers!

 

[doug293cz]

this is something I've still not worked out - I've got the strike part of the mash understood fine - but then I'm doing two batch sparges at 77C (which takes it to <70C grain temp at that point) but I don't know why I'm using 77C but that's the number I keep reading:

1. what temp should grain be for the batch sparge? and why?

2. when I do the batch how long do I leave it before drawing the wort off?

I don't think I've got a problem in this area - but I don't understand why I'm doing what I'm doing

any help appreciated

The grain does not have to be at any particular temp for batch sparge, if the conversion has run to completion. If conversion is complete, Kai Troester has shown that cold water batch sparge gives the same results as hot water sparge. If conversion isn't complete at the end of the mash, then using hot water extends the mash time, and may accelerate it if the temp rises, allowing more conversion to take place, until all of the enzymes are denatured.

Rest time in batch sparging is much less important than mixing (stirring.) After you have completed the initial run-off, the grits are coated in high gravity wort. What you want to happen, before you run off the sparge, is for the high gravity wort to be homogenized with the sparge water. This way you leave the least amount of sugar clinging to the grits after the sparge run-off. Stirring works much faster than diffusion for homogenizing the wort. Give the wort a good 5 minute stir, and then run-off immediately.

If you want to fix the sugar profile (prevent the wort from getting more fermentable) during the sparge, just start heating the first runnings to a boil as soon as you get enough wort in your BK.

Brew on

 

[kenack]

Thanks for all the comments and help. This weekend I did two 12 gallon batches using the batch sparge method and achieved 84% mash efficiency. I fell that this is going to be method from now on. I added 2 gallons after a 60 minute mash and kept the rims tube recirculating with out heat for 10 minutes then drained the wort into boil kettle, then pumped 7.5 gallons into my mashtun, stirred the mash and recirculated again for 10 minutes before draining into kettle. It's quicker than fly sparging and you don't have to watch over the flow during the whole time.

Thanks again!
Ken

 

[doug293cz]

Efficiency looks good. Glad you're happy with the new process.

There's no reason you can't include that 2 gal in the strike water. There is nothing magical about a 1.25 qt/lb (or any other) mash thickness. A thinner mash will actually convert a little faster than a thicker mash. This will cut a little time off of you brew day. 7.5 gal for the sparge water volume sounds pretty close to optimal.

Brew on

 

[Smellyglove]

To get the temp in the mash up to sparge temp you need to do a mash out in the mashtun first, raising the temperature to mashout, then start the sparge. Mashout temps makes the wort less viscous so it's easier to rinse out the sugars, as well as denaturing the enzymes so you "lock" in your mashing profile, or else the enzymatic reactions will continue.

 

[eric19312]

whether or not hot sparge water will increase extraction (at least some who have done experiments say it does not) , hot sparge water means less time to get your kettle to a boil. I normally start with 13.5 gallons in my kettle and one of the things I try to do to streamline my brew day is reduce the amount of time it takes to get to a boil. I boil with natural gas, it is quiet and I am not afraid of boiling in the garage with door 80% closed during the winter and I never have to go to the store to get it filled up. But it is not as hot as a high pressure propane burner. Making sure the wort going into the boil kettle is as hot as it can safely be helps. I also have the boil kettle burner on about 50% during lauter, cranking it up to 100$ last 3-4 gallons and with care I can be at a rolling boil just a few minutes after I stop the lauter.

 

[doug293cz]

To get the temp in the mash up to sparge temp you need to do a mash out in the mashtun first, raising the temperature to mashout, then start the sparge. Mashout temps makes the wort less viscous so it's easier to rinse out the sugars, as well as denaturing the enzymes so you "lock" in your mashing profile, or else the enzymatic reactions will continue.

There is no specific temp you need to hit in order to do a sparge, and you don't NEED to do a mash out. If you are planning to do a long fly sparge, and want to limit the increase in the fermentability of the wort during the sparge, then a mash out is a good idea. A 20°P (1.083) wort will have a viscosity decrease of about 16% on going from 150°F to 170°F, not a huge drop. The viscosity drop due to dilution by the sparge water will be much more significant.

Brew on