Not sure if fly sparging correctly

[jceg316]

Hey everyone, I got a whole new system a couple of months ago and have done maybe 5 brews on it. I keep getting lower gravities than I would on my older system and I think it's down to my sparging.

As I now have 50 litre SS kit, I use a pump to move liquids from one vessel to another. I usually only brew about 25 litres each time (FV volume) as I don't yet want to brew a full 50L. as an example, here's what I brewed yesterday:

5kg MO
500g light crystal malt
500g munich

used just under 18L of mash water
used 15 litres of sparge water.

Boiled for an hour, probably lost 4 litres in the boil.

this time I only had ~18L in fermenter, OG=1.049. Seems pretty low.

I used to have a sparge arm but it doesn't "fit" my new system. Instead I have an inlet tap at 9 oclock at the top of my MT (so I can incorporate a HERMS system) and I have a right angled barb with a small bit of hosing on to gently pour water onto the grain bed. I have a sheet of tin foil with holes pierced in it lying on top of the grain bed so the flow doesn't create a channel .

I think the inflow is more than the outflow as I need to top up the water in the MT so it's 2 inches above the grain bed. Once this happens does it matter that water is only being poured on on one place in the MT?

But does this all sound correct? I think I might be sparging too fast or maybe my water ratios are off?

Thanks for your help.

 

[helterscelter]

Hey everyone, I got a whole new system a couple of months ago and have done maybe 5 brews on it. I keep getting lower gravities than I would on my older system and I think it's down to my sparging.

As I now have 50 litre SS kit, I use a pump to move liquids from one vessel to another. I usually only brew about 25 litres each time (FV volume) as I don't yet want to brew a full 50L. as an example, here's what I brewed yesterday:

5kg MO
500g light crystal malt
500g munich

used just under 18L of mash water
used 15 litres of sparge water.

Boiled for an hour, probably lost 4 litres in the boil.

this time I only had ~18L in fermenter, OG=1.049. Seems pretty low.

I used to have a sparge arm but it doesn't "fit" my new system. Instead I have an inlet tap at 9 oclock at the top of my MT (so I can incorporate a HERMS system) and I have a right angled barb with a small bit of hosing on to gently pour water onto the grain bed. I have a sheet of tin foil with holes pierced in it lying on top of the grain bed so the flow doesn't create a channel .

I think the inflow is more than the outflow as I need to top up the water in the MT so it's 2 inches above the grain bed. Once this happens does it matter that water is only being poured on on one place in the MT?

But does this all sound correct? I think I might be sparging too fast or maybe my water ratios are off?

Thanks for your help.

I currently fly sparge much the same way you describe -- tinfoil with holes. it works well for me. the only problem I have is that when my water level is right (couple inches above the grain bed) the foil tends to want to float/move all over the place, so I have to keep an eye on it to keep it in the right place.

You just need to make sure you are not getting channelling and that your flow rate in and out are the same. and slow. a good way to ensure your in/out rates is with an o-ring around your sight glass.. put it on the glass at your MT's water level when you start your sparge and watch the relative height in the sight glass vs the location of your o-ring. if the level is above the o-ring, your inlet speed is too high relative to the outlet speed.. if the level is low, your outlet speed is faster than your inlet. I typically set my wanted outlet flow rate and then adjust the inlet speed accordingly.

 

[J-Rock44]

That is an awesome idea about the O-Ring and sight glass. I will try it. One thing I've been debating to try is I have an old (well not old, just not ever been used or opened) shower head that I have kept around for some reason. I originally bought it for the shower faucet components and the head was just part of the kit. I'm thinking of using the head for fly sparging. It's fairly large and distributes water really well so channeling shouldn't be a problem.

Anyone see anything flawed about this??

 

[helterscelter]

That is an awesome idea about the O-Ring and sight glass. I will try it. One thing I've been debating to try is I have an old (well not old, just not ever been used or opened) shower head that I have kept around for some reason. I originally bought it for the shower faucet components and the head was just part of the kit. I'm thinking of using the head for fly sparging. It's fairly large and distributes water really well so channeling shouldn't be a problem.

Anyone see anything flawed about this??

I'm not certain if shower heads are "food safe".. obviously they can't impart anything which is patently toxic, but I suspect they will happily leech off-flavors into your wort. I also doubt they are meant to handle 170f liquids. seems you would be much better off with a home-made sparge arm, rather than using a shower head. maybe try it out with hot water and see if you notice any smells or flavors in the water?

 

[jceg316]

Thanks for your reply. Whilst that O ring idea is really good, my MT doesn't have a sight glass. I think I need to be more careful with in/out flow rates.

In another forum someone said it's not good to have the sparge water in one place, but if I have 2 inches of water I'm not sure what the issue would be?

 

[afro_lou]

I think I might be sparging too fast or maybe my water ratios are off?

You may be on to something there... How long did you sparge for? The first couple AG brews I did with a sparge arm, I sparged too fast and lost a bunch of gravity points as well.

In another forum someone said it's not good to have the sparge water in one place, but if I have 2 inches of water I'm not sure what the issue would be?

I think it is still possible for the water to channel even with a couple of inches of depth above the grain bed, so it can be safer to make sure your sparge arm is lightly showering.

 

[doug293cz]

If you have a couple of inches of water on top of the grain bed, and the entering sparge water does not disturb the top of the grain bed, then that will not be the cause of any channeling, no matter how the water is distributed when added. If you do have channeling in this situation, then it has something to do with the flow patterns at the bottom of the MLT into the outlet.

Sparging too fast will encourage channeling, even with good flow patterns in the bottom of the MLT. Sparging too fast, even without channeling, will adversely affect your efficiency. This is because the water moves thru the grain faster than the retained sugar can diffuse into the water.

Brew on

 

[douglasbarbin]

+1 for you may be sparging too fast. Also, how does your grain crush look?

 

[beskone]

Flow rate is super important, you want to drain / add very slowly. It takes me about 60-70 minutes to complete a sparge.

After about 10 -15 minutes you should see crystal clear water above the grain bed as it pushes the sugary wort out the mash tun like a piston. If you're adding too fast, it'll stay murky and that's not going to be optimal for efficiency.

Here's what my janky diy sparge setup looks like in action at the start and about 10 minutes in:

https://vid.me/vj1W

https://vid.me/EkMh

 

[jceg316]

If you do have channeling in this situation, then it has something to do with the flow patterns at the bottom of the MLT into the outlet.

Interesting. A guy built my mash tun and the drain is on the side but underneath the false bottom. I asked if I needed a pipe to make it a centre drain but he said as the drain was below the false bottom this was not necessary.

I sparge for maybe 30-45 mins which seems a bit short compared to my last setup, where I would sparge for 45 mins - 1 hour.

My crushed grain are fine, I buy them precrushed from the store, who probably get it precrushed from the maltster.

Thanks for your help.

 

[doug293cz]

Interesting. A guy built my mash tun and the drain is on the side but underneath the false bottom. I asked if I needed a pipe to make it a centre drain but he said as the drain was below the false bottom this was not necessary.

I sparge for maybe 30-45 mins which seems a bit short compared to my last setup, where I would sparge for 45 mins - 1 hour.

My crushed grain are fine, I buy them precrushed from the store, who probably get it precrushed from the maltster.

Thanks for your help.

Drain location under a false bottom won't matter much, if you drain slowly enough. You might get away with a little bit higher run off rate with a center drain, but not sure it's worth the effort to move the drain. Increase your run off times to what you used on your old system. This should help.

Brew on

 

[jceg316]

OK thanks, I really think that it's down to draining too quickly. As it's a new system I'm still getting used to it. I have a pump as I plan to turn it into a HERMS, plus it's useful as my vessels are on the same tier so I use it to transfer liquor into the MT. It's also handy for vorlauf - just switch on the pump and recirculate.

However for some reason when it comes to sparge the pump gets loads of air in and it takes ages to get working which probably doesn't help.

 

[doug293cz]

OK thanks, I really think that it's down to draining too quickly. As it's a new system I'm still getting used to it. I have a pump as I plan to turn it into a HERMS, plus it's useful as my vessels are on the same tier so I use it to transfer liquor into the MT. It's also handy for vorlauf - just switch on the pump and recirculate.

However for some reason when it comes to sparge the pump gets loads of air in and it takes ages to get working which probably doesn't help.

Are you throttling flow with the MLT drain valve or a valve on the outlet side of the pump?
Pumps must be throttled on the outlet to prevent cavitation. Sounds like you might be experiencing cavitation. Over the long term cavitation can damage the pump impeller.

Brew on

 

[J-Rock44]

That's an awesome point I didn't even think of. Thank you so much for the reply, as you have probably saved me loads of pain and frustration.

Cheers!!

 

[douglasbarbin]

Are you throttling flow with the MLT drain valve or a valve on the outlet side of the pump?
Pumps must be throttled on the outlet to prevent cavitation. Sounds like you might be experiencing cavitation. Over the long term cavitation can damage the pump impeller.

Brew on

On a side note, I had problems similar to the OP until I installed 2 valves on the outlet side of my pump. One is to prime the pump and the other is to restrict output. This is the exact way mine is set up:

https://www.love2brew.com/Articles.asp?ID=604

 

[jceg316]

Are you throttling flow with the MLT drain valve or a valve on the outlet side of the pump?
Pumps must be throttled on the outlet to prevent cavitation. Sounds like you might be experiencing cavitation. Over the long term cavitation can damage the pump impeller.

Brew on

The it's set up is I have a magnetically coupled pump, I don't know much about pumps but apparently that means its flow rate can be controlled from the outlet of the pump. So I have a ball valve on my HLT I keep open at full whack, no taps on my pump, and one ball valve on the inlet on my mash tun. This is the one I use for controlling the flow rate. This works fine for transferring liquor to the MT for dough in, and also for recirculating the wort, but for some reason the pump gets all upset when it comes to sparge.

 

[doug293cz]

The it's set up is I have a magnetically coupled pump, I don't know much about pumps but apparently that means its flow rate can be controlled from the outlet of the pump. So I have a ball valve on my HLT I keep open at full whack, no taps on my pump, and one ball valve on the inlet on my mash tun. This is the one I use for controlling the flow rate. This works fine for transferring liquor to the MT for dough in, and also for recirculating the wort, but for some reason the pump gets all upset when it comes to sparge.

Magnetically coupled means that the impeller is not mounted on the motor shaft, and the motor shaft does not penetrate the pump body. Because the motor shaft does not penetrate the pump body, there is no shaft seal required. Shaft seals can, and usually do, leak over time. Instead there is a strong magnet on the end of the shaft (outside of the pump) and another strong magnet on the impeller shaft on the inside of the pump. The motor torque is transfered from one magnet to the other. In many pumps the magnetic coupling is strong enough that if the impeller jams, it will stop the motor from turning. Magnetically coupled pumps are good for sanitary uses, pumping noxious or corrosive liquids, or anywhere you really don't want to worry about leaks around a shaft seal.

That said, being magnetically coupled has nothing to do with needing to, or being able to, throttle pump flow on the outlet of the pump. If the inlet of the pump is throttled, the pump can create a vacuum internally because it can't pull in as much liquid as it has pushed out. The low pressure inside the pump can cause the liquid to boil, creating gas bubbles. This is cavitation. The closer the temp of the liquid being pumped is to its boiling point, the easier it is for a pump to cavitate while trying to pump it. You can't create a vacuum in the pump if you control the flow on the outlet, and leave the inlet wide open (unless something else restricts the input, like a stuck sparge.)

So, your pump may be having trouble during the sparge because the grain bed is restricting flow into the pump more than the valve is restricting outflow from the pump. In this case you would need to restrict the pump outlet valve even more.

Brew on

 

[jceg316]

Thanks for your help so far, it's been really useful. Especially what you say about cavitation: This would make sense as the mash water is ~75c, wort would be ~65 but sparge water is ~80-85 so it's more likely to cavitate. It would have nothing to do with the sparge though as the water is being drawn from the hot liquor tank. If I close off the out tap from the HLT a bit should this help prevent cavitation?

 

[douglasbarbin]

Thanks for your help so far, it's been really useful. Especially what you say about cavitation: This would make sense as the mash water is ~75c, wort would be ~65 but sparge water is ~80-85 so it's more likely to cavitate. It would have nothing to do with the sparge though as the water is being drawn from the hot liquor tank. If I close off the out tap from the HLT a bit should this help prevent cavitation?

No. Closing the valve on the HLT will increase the likelihood of cavitation. You want the HLT to be wide open going to the pump. You want to restrict the OUTPUT side of the pump (i.e., the water or wort leaving the pump).

In the case of sparging, you want the HLT valve wide open and you would restrict the flow using the valve on the output side of the pump (i.e., the water going to the mash tun).

 

[jceg316]

I did a brew today and sparged much slower than I usually do and my efficiency increased quite a bit. I still had some trouble with the pump, even when restricting flow on the MT inlet but I just need to play around.

My recipe was 4.5 kg maris otter
550g wheat
Mashed in with ~16 litres water
Sparged with ~13 litres

Wasn't enough sparge water, ended up with 22.5 litres in the boil, 20 in the FV. My OG was 1.052 which was the target, but ultimately the OG should have been higher as there was less water than I should have collected.

Not perfect but it's an improvement. The input of water in the mash tun was not even with wort draining as the pump kept stopping.

 

[doug293cz]

I did a brew today and sparged much slower than I usually do and my efficiency increased quite a bit. I still had some trouble with the pump, even when restricting flow on the MT inlet but I just need to play around.

My recipe was 4.5 kg maris otter
550g wheat
Mashed in with ~16 litres water
Sparged with ~13 litres

Wasn't enough sparge water, ended up with 22.5 litres in the boil, 20 in the FV. My OG was 1.052 which was the target, but ultimately the OG should have been higher as there was less water than I should have collected.

Not perfect but it's an improvement. The input of water in the mash tun was not even with wort draining as the pump kept stopping.

Do you have some pictures of your plumbing? Giving the folks here a look might allow them to pick up on something you missed.

Brew on

 

[douglasbarbin]

I did a brew today and sparged much slower than I usually do and my efficiency increased quite a bit. I still had some trouble with the pump, even when restricting flow on the MT inlet but I just need to play around.

Set your pump up like this:

https://www.love2brew.com/Articles.asp?ID=604

and you won't have any more problems.

 

[jceg316]

Set your pump up like this:

https://www.love2brew.com/Articles.asp?ID=604

and you won't have any more problems.

That bleed valve looks interesting, I wish he'd go into more detail but I will look it up elsewhere.

I will take photos and if possible a video when I'm next with my kit. I brew at my parents' house in the suburbs as they have the space and not at my place.

 

[jceg316]

Just want to revive this again as I've brewed today and it seemed to go well. I set up a bleeder valve on my pump and it ran really well. Thank you douglasbarbin for pointing me in the right direction.

Got my old sparge arm working as well. Sparged really slowly but want to know whether my numbers make sense. A full brew report can be found on brewtoad:https://www.brewtoad.com/recipes/archduke-franz-ferdinhandz but to cut it short:

7.4 kg maris otter
0.6kg light caramalt
0.6kg candi sugar.

Mash 1 hour
Boil 1 hour

30 litres pre boil, 25 post.

OG: 1.077.

It's the highest gravity I've had since I got my new kit but does the efficiency sound alright or am I still having issues?

Thanks.

 

[Gavin C]

Just want to revive this again as I've brewed today and it seemed to go well. I set up a bleeder valve on my pump and it ran really well. Thank you douglasbarbin for pointing me in the right direction.

Got my old sparge arm working as well. Sparged really slowly but want to know whether my numbers make sense. A full brew report can be found on brewtoad:https://www.brewtoad.com/recipes/archduke-franz-ferdinhandz but to cut it short:

7.4 kg maris otter
0.6kg light caramalt
0.6kg candi sugar.

Mash 1 hour
Boil 1 hour

30 litres pre boil, 25 post.

OG: 1.077.

It's the highest gravity I've had since I got my new kit but does the efficiency sound alright or am I still having issues?

Thanks.

Mash efficiency at 75% is low pointing to somewhat poor

• conversion
• lautering
• both

or excessive mash-tun dead space

Your planned OG was 1.082?

 

[jceg316]

Mash efficiency at 75% is low pointing to somewhat poor

• conversion
• lautering
• both

or excessive mash-tun dead space

Your planned OG was 1.082?

I put the recipe & ingredients in and Brewtoad spat out the numbers. Just checking the original recipe this is based on and yeah I guess 1.082 is the target, however I don't know what efficiency they are brewing at.

Sparging was slow, it took about 1 hour or so to get 30 litres out. Mash temperature started at 66C but dropped by the end of the mash to 62C, which I imagine wouldn't help.

 

[Gavin C]

You mentioned earlier in the thread about your crush being satisfactory, buying pre crushed grains from the homebrewstore who in turn gets them pre crushed from a supplier.

if this is indeed the case, these are not grains I would buy. If your going to invest time and money in a swanky setup with a sparge arm I would recommend investing in your own mill. It will be fresher and you can crush it as fine as you want aiming for as fine a crush as possible without getting a stuck sparge.

I do no sparge brewing with an unblockable manifold. Freshly crushed grain at the finest setting my mill has. Mash efficiency typically is 85-90%

Your problems may be occurring before you ever get to a sparge process

What was the planned efficiency on the batch? What was the mash efficiency and subsequent brewhouse efficiency.

Edit: mash temeprature instability does not help with controlling the planned fermentability, but would likely only minimally impact the actual mash efficiency. Really depends on the grain quality and crush i would suggest.

 

[douglasbarbin]

Edit: mash temeprature instability does not help with controlling the planned fermentability, but would likely only minimally impact the actual mash efficiency. Really depends on the grain quality and crush i would suggest.

Mash pH is important as well.

 

[Gavin C]

Mash pH is important as well.

It does effect the differing enzymatic activity in the mash but is very much of secondary importance when it comes to efficiency. Grain crush, mash consistency, temperature and lautering effectiveness have much greater an impact.

Mash pH has a much greater bearing on flavor and other subjective attributes of the final beer. It is possible to have very high mash efficiencies and have the pH very much out of ideal range.

But it certainly does play a role albeit a minor one.

If the other mash mechanics are off, nailing the pH down won't improve the mash efficiency to any significant extent.

Edit: I guess you may just have been referring to fermentability. Sorry @douglasbarbin about that tangental redundant info.

 

[jceg316]

I'm not sure grain crush would improve efficiency to an extent I'm looking to improve efficiency. This is the crush I usually have and my efficiency was fine. At this stage crushing my own grain would be more hassle than it's worth, especially as it needs to be just right for maximum efficiency.

There's something bigger, like maybe water/grain ratio or something else to do with the mash.

How would dead space in the mash tun effect efficiency ?