Fly Sparging Temperature & Flowrate

[stephelton]

Couple quick questions I'd like to ask before I do my next fly sparge:

1) After mashing, it is important to bring the temperature up quickly to halt enzymatic activity, right? This should be > 170 degrees F as I recall. It would take a long time for the temperature to reach that point unless I either use extremely hot water, or start the sparge off very quickly. What do others do to accomplish this?

2) What flowrate to you/others establish when fly sparging? I've been shooting for about 1 qt per minute per some advice from a LHBS employee. Should I vary this? The wiki page here on fly sparging claims the sparging process could take an hour or more.

3) [Tying the two together]: Should I start out faster until a lot of the original mash water has been run off?

Thanks a lot.

 

[drayman86]

Couple quick questions I'd like to ask before I do my next fly sparge:

1) After mashing, it is important to bring the temperature up quickly to halt enzymatic activity, right? This should be > 170 degrees F as I recall. It would take a long time for the temperature to reach that point unless I either use extremely hot water, or start the sparge off very quickly. What do others do to accomplish this?

I fly sparge exclusively, and never worry about a mash out. I use water at about 175F.

2) What flowrate to you/others establish when fly sparging? I've been shooting for about 1 qt per minute per some advice from a LHBS employee. Should I vary this? The wiki page here on fly sparging claims the sparging process could take an hour or more.

That's about the flow rate you're shooting for. Although it takes a while, be patient; you'll be rewarded with a great efficiency.

3) [Tying the two together]: Should I start out faster until a lot of the original mash water has been run off?

NO. You might as well batch sparge.

Remember the concept with fly sparging; we're attempting to gradually rinse the sugars from the grain with a steady, evenly distributed flow of water through the grain bed.

You'll find no end of discussions on batch vs. fly sparging here. It's typically a personal preference based on what works with your equipment and techniques. I prefer fly sparging. Takes a bit longer, but it's basically an automatic process once you get the flow rates dialed in. Don't forget to keep a couple of inches of water above your grain bed to avoid introducing oxygen/oxidation into the process.

 

[menschmaschine]

1) After mashing, it is important to bring the temperature up quickly to halt enzymatic activity, right? This should be > 170 degrees F as I recall. It would take a long time for the temperature to reach that point unless I either use extremely hot water, or start the sparge off very quickly. What do others do to accomplish this?.

There's somewhat of a misconception there. In a mash-out, enzyme activity doesn't stop altogether. Alpha amylase is still somewhat active. The primary reason for mash-out is to make the mash easier to lauter, i.e. the higher temp. reduces mash density and puts more sugars into solution (rather than clinging to grain particles), but it's not so high to risk tannin extraction (180°F). The only thing you really risk by not doing a mash-out when fly-sparging is lauter efficiency. I have a direct-fired mash tun, so mash out is a snap. You can do a mash-out with a hot water infusion or a thin decoction.

2) What flowrate to you/others establish when fly sparging? I've been shooting for about 1 qt per minute per some advice from a LHBS employee. Should I vary this? The wiki page here on fly sparging claims the sparging process could take an hour or more..

Personally, I think it depends on your fly-sparge technique. If you use a sparging device (arm), then a typical 5 gallon batch should take at least 45 min., but more like an hour. With my method, I go full bore, i.e. as much as my 3/8" dip-tube in my MLT will allow. I take a length of tubing from my HLT and allow the hot water to flow all over the grain bed randomly (by hand). The flow of water disturbs the grain bed enough (initiating channeling at random locations) to release the sugars. I get very high efficiency (90%+)and from opening the valves to closing, I'm done in 30 min... and have ~14.5 gallons in the boil kettle. That's against homebrewing convention, but it works for me and I don't know of any detriment that it could cause.

3) [Tying the two together]: Should I start out faster until a lot of the original mash water has been run off?

A steady flow from beginning to end is fine.
EDIT: You want to keep ~1-2" of water over the grain bed all the time.

 

[Boerderij_Kabouter]

Personally, I think it depends on your fly-sparge technique. If you use a sparging device (arm), then a typical 5 gallon batch should take at least 45 min., but more like an hour. With my method, I go full bore, i.e. as much as my 3/8" dip-tube in my MLT will allow. I take a length of tubing from my HLT and allow the hot water to flow all over the grain bed randomly (by hand). The flow of water disturbs the grain bed enough (initiating channeling at random locations) to release the sugars. I get very high efficiency (90%+)and from opening the valves to closing, I'm done in 30 min... and have ~14.5 gallons in the boil kettle. That's against homebrewing convention, but it works for me and I don't know of any detriment that it could cause.

I use this technique as well. It was prescribed to me by my LHBS owner and has served me very well. I sight in a 80% efficiency and get right on every time. I don't want to go any higher than that and this technique works perfectly for me.

 

[SpanishCastleAle]

All I've ever done is fly sparge and it works for me so that's why I stick with it.

1) I mash in a pot so I just add heat but sometimes I'll do a thin-mash decoction and use that. As mensch mentioned...it's not to halt enzyme activity, it's to increase lauter efficiency.

2) I've never measured it...I just eyeball it...but I think I'm going a little faster than that.

3) You should probably start your sparge at a slow, steady rate but towards the end when the wort gets at/near the bottom of the grain bed you can open the valve full bore (at that point you're pretty much just draining the remaining liquid anyway). It's the very beginning of the sparge where it's more important to keep it slow. For me, 6-6.5 gallons of runoff takes ~30 minutes which is apparently faster than some...but then my crush isn't as fine as some either.

This gets me ~85% brewhouse efficiency (into the fermenter) with a .040" crush.

 

[menschmaschine]

I use this technique as well. It was prescribed to me by my LHBS owner

Lucky you... mine was trial and error (except without the error).

 

[stephelton]

Thanks for the valuable input. I'm heating the water now (been waiting on the yeast starter to show signs of life

I described my MLT over on my blog. I'll take a few pictures of the whole system in action when the time comes.

 

[squeekysheep]

is that just gravity pushing water into the mash ton ?

 

[stephelton]

is that just gravity pushing water into the mash ton ?

Yeah, if you take a look again, I've updated it with a couple pictures I took today. That's why it's sitting atop the fridge

 

[Piotr]

I take a length of tubing from my HLT and allow the hot water to flow all over the grain bed randomly (by hand). The flow of water disturbs the grain bed enough (initiating channeling at random locations) to release the sugars.

I don't think you should disturb the grain bed while fly-sparging. Im my case I pour the water carefully on a small plate, which I lay on the surface of the grain bed

 

[menschmaschine]

I don't think you should disturb the grain bed while fly-sparging.

Why not? Is it to prevent channeling? Yes you want to prevent channeling in a static system, but if the water outlet is constantly and randomly moving over the grain bed... and disturbing just the top of the grain bed, it can only help with lauter efficiency.

 

[SpanishCastleAle]

Just curious mensch but how does that make a difference? There is an inch or two of water/wort above the top of the grain bed so whether the sparge arm is moving or not shouldn't make much difference...should it? What am I missing?

I use an extremely high-tech method (in my equally high-tech 'bucket-in-a-bucket' lauter tun ). Once the mash is in the lauter tun I just place a disc-shaped, convex wire mesh screen on top of the mash and then place a collander on top of that. Then just use a saucepot to pour the first runnings/sparge water in the collander and let it disperse the liquid on top of the mash (most of it goes down the middle which is fine).

 

[stephelton]

I don't think you should disturb the grain bed while fly-sparging. Im my case I pour the water carefully on a small plate, which I lay on the surface of the grain bed

Yeah, that was contrary to everything I've heard so far...

 

[Boerderij_Kabouter]

You want to disturb the "crust" of the mash during the sparge. Big brewers use a machine called a mash rake to constantly mix the mash during the sparge. They only leave about 6 inches or something like that static during the sparge.

Disturbing the surface prevents channeling because during the course of the sparge, proteins will form a skin over the mash and direct water into a limited number of areas. This effect is especially visible in a beer with a high proportion of wheat.

It would be nice to be able to use mash rakes, but for our small mash size they do not make sense. By splashing the water for the sparge by hand, the force of the water falling into the tun can be used to at least slightly disturb the surface. I like how this works, and it has yielded great results for me.

 

[Boerderij_Kabouter]

Here is a thread similar to what I am talking about.

https://www.homebrewtalk.com/f11/lauter-rakes-21072/

 

[Piotr]

This is how I understand fly sparging:

The process has 2 stages:
1. Pushing down the liquid wort trapped between the grains
2. Extracting the rest of the sugars (by osmosis) from the interior of the grain

Disturbing the grain bed is not good, because water should form a "piston" over the wort to push it all down, and we should prevent mixing wort and water.

Maybe in the second stage mixing grains will help in better sugar extraxtion, but I try to limit all my sparging process to first stage only, to minimize tanin extraction etc.

 

[menschmaschine]

Just curious mensch but how does that make a difference? There is an inch or two of water/wort above the top of the grain bed so whether the sparge arm is moving or not shouldn't make much difference...should it? What am I missing?

By having the water exit at one point (instead of multiple), there is a greater flow rate (with gravity anyway). So, imagine a good steady stream from a piece of tubing hitting the water on top of the grain bed... it will cause a disturbance in the grain bed because of the flow-rate. And because it's done by the brewer instead of a mechanical device, it is completely random. So, virtually no area of the grain bed will be missed.

The result is that the whole surface area of the grain bed is being lightly stirred up. This gets the sugars off the grains and into the wort better. Also, very light channeling occurs practically everywhere as well over the course of the sparge. This draws those sugars to the MLT output quicker. All of this put together results in a faster, more efficient sparge technique.

Am I explaining it well? I wish I could do an animated drawing of a cross-section of the MLT to portray what I'm envisioning.

 

[menschmaschine]

Disturbing the grain bed is not good, because water should form a "piston" over the wort to push it all down, and we should prevent mixing wort and water.

Maybe in the second stage mixing grains will help in better sugar extraxtion, but I try to limit all my sparging process to first stage only, to minimize tanin extraction etc.

But wouldn't that make batch sparging "bad"? Tannin extraction is a function of temperature and pH. Stay under ~180°F (82°C) and your pH under control (don't recall exact number... 8.0?) and you won't get tannin extraction. So, if your water source has a relatively high pH, you can add acid to the sparge water to compensate.

 

[Piotr]

Tannin extraction is a function of temperature and pH. Stay under ~180°F (82°C) and your pH under control (don't recall exact number... 8.0?) and you won't get tannin extraction. So, if your water source has a relatively high pH, you can add acid to the sparge water to compensate.

I do, but still... There is a good anecdotal (and hopefully experimental) evidence that no-sparge method gives better beer. This method is too expensive for me, but I try to go half way towards it...

Another story: at the beginning of my brewing I tried to achieve best efficiency numbers. I tried all tricks with sparging: batch sparging, sparging with boiling water, mixing the grains constantly.
But it turned out, that best efficiency ever I got, when I wasn't disturbing the grain bed at all. So I sticked to that method, somehow it worked best for me. I see your efficiency is great, maybe your method is best for your system...

 

[menschmaschine]

But it turned out, that best efficiency ever I got, when I wasn't disturbing the grain bed at all. So I sticked to that method, somehow it worked best for me. I see your efficiency is great, maybe your method is best for your system...

That's all we can do... whatever works best for our system. I used to conduct long fly-sparges with slow water output as well. But I started to experiment with shorter times and noticed no difference in my efficiency. Finally I said, "OK, fine, I'm gonna go full bore and see what happens." I did and noticed no difference in efficiency or in the final beer. But like you said, that worked for my system and my be different for other brewers.

 

[SpanishCastleAle]

You described it well mensch. I just didn't realize there was enough 'force' behind the sparge water to disturb the grain that's under an inch or two of water...I had read to disturb the grain bed as little as possible but that was back when half of what I 'knew'...was a myth (now it's prob down to 33%).

I can see what Boerderij is saying about those fine particles that float to the top and form a bit of a crust. They sort of 'clog that portion of the filter' so to speak. If I used a fine/tight crush I imagine it would be even more so.

 

[tnbrewer371]

I fly sparge exclusively, and never worry about a mash out. I use water at about 175F.



That's about the flow rate you're shooting for. Although it takes a while, be patient; you'll be rewarded with a great efficiency.



NO. You might as well batch sparge.

Remember the concept with fly sparging; we're attempting to gradually rinse the sugars from the grain with a steady, evenly distributed flow of water through the grain bed.

You'll find no end of discussions on batch vs. fly sparging here. It's typically a personal preference based on what works with your equipment and techniques. I prefer fly sparging. Takes a bit longer, but it's basically an automatic process once you get the flow rates dialed in. Don't forget to keep a couple of inches of water above your grain bed to avoid introducing oxygen/oxidation into the process.

why dont batch spargers have this problem if this is true??

 

[WesternBrew]

Don't forget to keep a couple of inches of water above your grain bed to avoid introducing oxygen/oxidation into the process.

The mash is pre-boil(I have read that boiling removes oxygen) and you want to purposefully oxygenate the wort before you pitch anyway. Should I be worrying about oxydation at this point?