Fly Sparging - Efficiency Suffering

[KarmaCitra]

So I switched over to fly sparging mainly just because I like the process, but I've noticed that my efficiency has suffered as of late (in the low to mid 60s). I recirculate through my pump for about 10 mins, MLT lid closed (I have a sparge arm built into the lid)), then Iheat my sparge water to about 185°. I use that to sparge since my MLT is an igloo cooler and I'm not really into decoctions so I figured sparging with 185° will be OK. Am I doing something wrong? I try to keep about an inch or so of sparge water on the grain. Would it be bad if I were to start using 200° water throughout my sparge, or will that guarantee tannin extraction?

 

[doug293cz]

So I switched over to fly sparging mainly just because I like the process, but I've noticed that my efficiency has suffered as of late (in the low to mid 60s). I recirculate through my pump for about 10 mins, MLT lid closed (I have a sparge arm built into the lid)), then Iheat my sparge water to about 185°. I use that to sparge since my MLT is an igloo cooler and I'm not really into decoctions so I figured sparging with 185° will be OK. Am I doing something wrong? I try to keep about an inch or so of sparge water on the grain. Would it be bad if I were to start using 200° water throughout my sparge, or will that guarantee tannin extraction?

Increasing your sparge water temp won't improve your efficiency. Lauter efficiency issues with fly sparging are most often due to channeling, where most of the sparge water finds easy paths thru the grain bed, so that the bulk of the grain doesn't really get rinsed. Channeling can be caused by sparging too fast or having a sub-optimal geometry for the wort pick up in the bottom of the MLT. Do you have a braid, manifold or false bottom? A false bottom gives the best results, a correctly designed manifold gives almost as good results, and a braid is usually the most problematic for channeling.

It's also possible that your conversion efficiency is suffering. You can determine your conversion efficiency by measuring the wort SG in your MLT at the end of your mash. Then use the calculation method described here. If your conversion efficiency is less than 95%, then you may want to focus on improving it. If your conversion efficiency is better than 95%, then your low efficiency is due to lauter issues.

Brew on

 

[KarmaCitra]

I'm using a false bottom. My sparge takes about 30-45 mins. I'm wondering if I just need to really slow it all down. I'll try the method you described about the conversion efficiency.

 

[KarmaCitra]

If when recirculating I am losing temperature, shouldn't my sparge water be hotter than usual in order to capture the sugars?

 

[RM-MN]

If when recirculating I am losing temperature, shouldn't my sparge water be hotter than usual in order to capture the sugars?

It makes little difference whether to use hot water or cool so your going hotter probably makes no noticeable difference in the amount of sugars caprtured.

 

[Redlantern]

Bad efficiency causes:
1) grain crush
2) pH
3) grain bed not set and channeling
4) stale grain
5) wrong mash temp


Sparge time seems just fine. Taste the grain after sparge. a lot of sugar? if so, ineffective sparge process. No benefit to raising sparge temp far as I know. Only a down-side of tannins. Gut tells me that it is a conversion issue that coincided with changing to fly sparging

 

[KarmaCitra]

Bad efficiency causes:
1) grain crush
2) pH
3) grain bed not set and channeling
4) stale grain
5) wrong mash temp


Sparge time seems just fine. Taste the grain after sparge. a lot of sugar? if so, ineffective sparge process. No benefit to raising sparge temp far as I know. Only a down-side of tannins. Gut tells me that it is a conversion issue that coincided with changing to fly sparging

The crush I do is the .05 setting and seems to be normal. pH was about 4.6 according to the test strip. Not sure of the freshness of the grain, as I got it from my LHBS but it seemed OK. Mash temp was 148°.

I think something is going on either with the grain bed not setting or just my sparge process in general. I am having a tough time matching the inflow rate of sparge water to the outflow of wort into the kettle. I noticed a few times yesterday that my sparge water was either too high (more than 1-2" of water on top of grain bed), or the bed was fully out of water so I had to adjust and get more sparge water in there.

 

[Yooper]

The crush I do is the .05 setting and seems to be normal. pH was about 4.6 according to the test strip. Not sure of the freshness of the grain, as I got it from my LHBS but it seemed OK. Mash temp was 148°.

I think something is going on either with the grain bed not setting or just my sparge process in general. I am having a tough time matching the inflow rate of sparge water to the outflow of wort into the kettle. I noticed a few times yesterday that my sparge water was either too high (more than 1-2" of water on top of grain bed), or the bed was fully out of water so I had to adjust and get more sparge water in there.

I crush at .032" or so, so your ".05" doesn't make sense to me. Your pH test strips are WAY off, as your mash should have been more like 5.4 or 5.5, but those strips aren't accurate anyway so I doubt your pH was that low unless you added a ton of acid.

In any case it sounds like you've got some channelling or something interfering with the sparge, and if the top of your grainbed isn't under the water by a couple of inches or so, that would explain it.

 

[KarmaCitra]

I crush at .032" or so, so your ".05" doesn't make sense to me. Your pH test strips are WAY off, as your mash should have been more like 5.4 or 5.5, but those strips aren't accurate anyway so I doubt your pH was that low unless you added a ton of acid.

In any case it sounds like you've got some channelling or something interfering with the sparge, and if the top of your grainbed isn't under the water by a couple of inches or so, that would explain it.

What do you mean by the .05 doesn't make sense? It's basically the middle setting on the mill. Should I try something like .03?

Yeah, the grain was under a few inches of water, then wasn't, then was, etc etc. It sounds like this could be my big issue. That sparge water isn't acting like a squeegee. Right?

 

[doug293cz]

If when recirculating I am losing temperature, shouldn't my sparge water be hotter than usual in order to capture the sugars?

All the sugar in the mash is in solution as it is created. There is no solid sugar anywhere to dissolve. At mash temperatures, 1 lb of water can dissolve 2 lb of maltose, which would have an SG somewhere around 1.300. Mashing at 1 qt/lb would result in a max wort SG of 1.114, which is almost 3X below the solubility limit. So, sugar solubility during sparging is never an issue. This is why hotter water won't improve your sparge efficiency.

Brew on

 

[KarmaCitra]

That makes sense.

 

[Redlantern]

my sparge technique has changed lately and I like the results.

I drain the wort until the bed settles and there is no liquid visible at the top. Form there, I close the mash tun valve, build up 2 inches of water, and start the flow back into the kettle. With a good set to the grain bed, the out flow is consistent and it is easier to control the sparge. Efficiency has been great.

 

[KarmaCitra]

my sparge technique has changed lately and I like the results.

I drain the wort until the bed settles and there is no liquid visible at the top. Form there, I close the mash tun valve, build up 2 inches of water, and start the flow back into the kettle. With a good set to the grain bed, the out flow is consistent and it is easier to control the sparge. Efficiency has been great.

I'm going to try that. So do you just drain until you can see grain with no water above it, or do you drain it completely?

 

[Redlantern]

I drain and watch the grain. It will begin to settle as the wort drains out.

You can see it move if you watch the sides of the mash tun and observe as the level drops. When the grain almost seems to stop settling and there is no wort visible on top, shut the valve and start running the sparge water until you get at least 2 inches on top of the grain bed. Slow down the sparge water to a trickle and crack the mash tun valve to begin sparging. With this method, I have gone as long as 25 minutes with no adjustment necessary to either valve and the water level almost did not change.

 

[KarmaCitra]

What temp is your sparge water?

 

[Redlantern]

165-168 ish

I only heat the sparge water so I can get to boil quicker

 

[day_trippr]

[...]When the grain almost seems to stop settling and there is no wort visible on top, shut the valve and start running the sparge water until you get at least 2 inches on top of the grain bed. [...]

Ah HAH! As I read that I realized I've never actually read of anyone espousing this method before on hbt. Might have missed it.
But I run a 3V two pump herms with an autosparge and that is exactly how I've always run my sparging process.
It just makes more sense to me than immediately adding in sparge liquor when there is rich wort standing atop the bed.

I recirculate the mash from 10 minutes after dough-in to hold temperature, then dial up the hlt to 168°F at the end of the mash, switch from recirculation to a very slow run-out, drain the standing wort 'til the floaties just come to a rest, then switch in the sparge as soon as it hits temperature.

The autosparge works perfectly (love that thing) to maintain a ~2" deep pool above the grain bed while I take a full hour to run off (11g into the fermentors). I routinely hit mash efficiencies over 90% while still keeping the end of run-off sg above 1.010 & ph below 5.6. Plenty of reason to keep doing it this way

Cheers!

 

[Denny]

All the sugar in the mash is in solution as it is created. There is no solid sugar anywhere to dissolve. At mash temperatures, 1 lb of water can dissolve 2 lb of maltose, which would have an SG somewhere around 1.300. Mashing at 1 qt/lb would result in a max wort SG of 1.114, which is almost 3X below the solubility limit. So, sugar solubility during sparging is never an issue. This is why hotter water won't improve your sparge efficiency.

Brew on

I just want to say "I love you, man"!

 

[doug293cz]

I just want to say "I love you, man"!

Thanks, that means a lot coming from one of the legends of homebrewing.

Brew on

 

[jgrreed]

We crush to .045, and fly sparge while being very careful to not create a negative pressure under the false bottom via a manometer.... works pretty good. Crushing to .03 worries me re: creating flour/dough, but if it works for you maybe I should tighten up the rollers??!!

If your pH is really that far off, maybe some 5.2 stabilizer crystals would help you out??

-Jer.

 

[a1226r]

The crush I do is the .05 setting and seems to be normal. pH was about 4.6 according to the test strip. Not sure of the freshness of the grain, as I got it from my LHBS but it seemed OK. Mash temp was 148°.

I think your crush setting is too wide. I crush between .036 and .040. Also when mashing at 148 for a dryer beer, mash time should be along the times of 70-90 mins. The lower mash temps require longer mash time.

Everything else you've described seems on point to me.

 

[norsk]

I just want to say "I love you, man"!

I must have said the same thing to you (In my head) numerous times many years ago when putting an end to sparging with hot water after reading your description of your evolution of batch sparging techniques...

 

[Brewbuzzard]

So I switched over to fly sparging mainly just because I like the process, but I've noticed that my efficiency has suffered as of late (in the low to mid 60s). I recirculate through my pump for about 10 mins, MLT lid closed (I have a sparge arm built into the lid)), then Iheat my sparge water to about 185°. I use that to sparge since my MLT is an igloo cooler and I'm not really into decoctions so I figured sparging with 185° will be OK. Am I doing something wrong? I try to keep about an inch or so of sparge water on the grain. Would it be bad if I were to start using 200° water throughout my sparge, or will that guarantee tannin extraction?

I recirculate at a rate of 1 qt per minute which is about 20 minutes for a 5 gal batch. I also cut my grain bed periodically, just a few inches deep will do. I think you are recirculating too fast and also letting you grain bed running dry. As for your crush, settings can differ from mill to mill. You just want to crack the kernel in to a few pieces and leave the husk whole (easier said than done). I always check my crush before crushing all the grain.

Prost!

 

[toddk63]

30 min is a tad fast. 45 min is just right.

 

[DrGMG]

Great discussion. Learned a lot.

 

[KarmaCitra]

The crush I do is the .05 setting and seems to be normal. pH was about 4.6 according to the test strip. Not sure of the freshness of the grain, as I got it from my LHBS but it seemed OK. Mash temp was 148°.

I think your crush setting is too wide. I crush between .036 and .040. Also when mashing at 148 for a dryer beer, mash time should be along the times of 70-90 mins. The lower mash temps require longer mash time.

Everything else you've described seems on point to me.

The mash likely sits for 75 minutes once I get the sparge water going. The recirculation time doesn't count toward the mash time, does it? Im leaving the mash tun alone for a full 60 mins, then recirculating for 10. I've never heard of a longer mash time with lower mash temps. Interesting!

 

[KarmaCitra]

I recirculate at a rate of 1 qt per minute which is about 20 minutes for a 5 gal batch. I also cut my grain bed periodically, just a few inches deep will do. I think you are recirculating too fast and also letting you grain bed running dry. As for your crush, settings can differ from mill to mill. You just want to crack the kernel in to a few pieces and leave the husk whole (easier said than done). I always check my crush before crushing all the grain.

Prost!

I'll try the 20 minute recirculation next time. I know the mash isn't running dry...In fact, I usually don't see the grains peek through between end of mash and while sparging. I saw in a previous post in this thread though that you should run the wort out of the MLT right until the grains start peeking out then run sparge water. Or at least that's how I understood it.

 

[kingof14ers]

I'd personally go an hour even on the sparge adjusting the flow rate based on how big of a batch or how much wort you're collecting.

Isn't the sugar more malleable with hot spare water and therefore more "rinseable" aside from the added obvious benefit of making the wort closer to boil afterward?

I would also look at you're thermometer and ensure accuracy. Describe what type you're using and what your technique is to determine your measurement. Also how are you adjusting your pH? Apologies if I missed that part.

 

[KarmaCitra]

I'd personally go an hour even on the sparge adjusting the flow rate based on how big of a batch or how much wort you're collecting.

Isn't the sugar more malleable with hot spare water and therefore more "rinseable" aside from the added obvious benefit of making the wort closer to boil afterward?

I would also look at you're thermometer and ensure accuracy. Describe what type you're using and what your technique is to determine your measurement. Also how are you adjusting your pH? Apologies if I missed that part.

I'm using a thermopen and it's calibrated. I'm not sold on the pH strips...I feel like I essentially wasted $8. I didn't add any acid to the mash and got 4.6. I'll probably get a digital one at some point.

 

[Denny]

Isn't the sugar more malleable with hot spare water and therefore more "rinseable" /QUOTE]

Not until you hit an SG of 1.300.

 

[kh54s10]

Previously did you batch sparge? Did you crush your own grain. What else has changed?

It seems most likely to be two possibilities:
1) poor crush.
2) channeling.

Or a combination of the two. If your drop in level below the top of the grain didn't last too long, I doubt that would have a large effect.

If you crush some grain and post the picture you will get opinions on how good your crush is.

 

[dyqik]

The mash likely sits for 75 minutes once I get the sparge water going. The recirculation time doesn't count toward the mash time, does it? Im leaving the mash tun alone for a full 60 mins, then recirculating for 10. I've never heard of a longer mash time with lower mash temps. Interesting!

I've been thinking a bit about the relatively low efficiency I get on my system with fly sparging.

I did a Heady clone this last weekend (recipe from on here), mashing at 148F and 1.5 qt/lb, with conditioned grain milled at 0.32" gap on my mill. I use a 10g cooler with a dome false bottom, recirculating via a RIMS tube controlled to 150F. pH was adjusted for my water using most of the gypsum addition called for in the Heady clone recipe, and measured at 5.4 at room temperature at 15 minutes into the mash. (right, that's the background over...)

Relevant to your post quoted above, I used my refractometer to check the SG of the recirculating wort during the 75 minute mash. That lets you check conversion efficiency separately from lautering/sparging efficiency, by comparing to the 100% extraction SG expected at your mash thickness (taken from Braukaiser). Conversion efficiency was 85% at 60 minutes, about 95% at 75 minutes.

I then did a mash out over 20 mins and fly sparged for about 30 minutes, eventually hitting 70% brewhouse efficiency, and about 75% mash efficiency. So my lauter efficiency wasn't great, but wasn't terrible either for a big beer. I can definitely do better on the sparge, because my final runnings gravity was about 1.020. I guess I could try a lower qt/lb so that I can use more sparge water into the kettle, or compare to batch sparging.

So I suggest you use a refractometer to measure conversion efficiency - this will identify issues with extraction from the grains due to the crush and wetting/recirculation, or incomplete conversion (although starch in solution also contributes to SG), vs lautering efficiency. Have a look at the Braukaiser link above as well, and see what you think you can improve.

 

[dyqik]

I'm using a thermopen and it's calibrated. I'm not sold on the pH strips...I feel like I essentially wasted $8. I didn't add any acid to the mash and got 4.6. I'll probably get a digital one at some point.

There's a note I've seen, I think in the Brew Science forum on one of the sticky threads or in Bru'n'water itself, about the plastic pH strips reading several points low in wort, possibly as much as 0.5 or so.

I now have a Milwaukee MW102 pH meter, and it's confirming that I'm getting very close to my pH targets in the mash using my Ward Lab test results and Bru'n'water. If you don't have a water test result, go for that first before getting a pH meter, unless you think you have very variable water.

 

[KarmaCitra]

I don't have a picture of the crush, but it am definitely cracking them, leaving husks and getting a bit of flour in the crush. I'll try to get a picture.

Channeling shouldn't happen with a false bottom, should it?

 

[dyqik]

Bad efficiency causes:

4) stale grain

How old do you think grain has to be to be stale and affect efficiency? The batch I mention above was done with TF Pearl malt as the base malt, bought two and half years ago in a group buy, but freshly milled.

 

[Redlantern]

Hard to say - if not crushed, keeps pretty well for a long time. If crushed, it starts (slowly) to go downhill immediately. If it was crushed two months ago and not stored well, I imagine the results would not be so good.

 

[doug293cz]

I don't have a picture of the crush, but it am definitely cracking them, leaving husks and getting a bit of flour in the crush. I'll try to get a picture.

Channeling shouldn't happen with a false bottom, should it?

Yes, you can get channeling with a false bottom. The FB just makes it easier to avoid channeling vs. the alternatives. If your lauter efficiency is low, it is almost certainly largely due to channeling. You must calculate your lauter efficiency from your measured mash and conversion efficiencies.

Lauter_Efficiency = Mash_Efficiency / Conversion_Efficiency​

Brew on

 

[Denny]

There's a note I've seen, I think in the Brew Science forum on one of the sticky threads or in Bru'n'water itself, about the plastic pH strips reading several points low in wort, possibly as much as 0.5 or so.

I now have a Milwaukee MW102 pH meter, and it's confirming that I'm getting very close to my pH targets in the mash using my Ward Lab test results and Bru'n'water. If you don't have a water test result, go for that first before getting a pH meter, unless you think you have very variable water.

It's .3 and even with that correction they still aren't very accurate.

 

[Denny]

I don't have a picture of the crush, but it am definitely cracking them, leaving husks and getting a bit of flour in the crush. I'll try to get a picture.

Channeling shouldn't happen with a false bottom, should it?

I'd say you need a finer crush. And of course you can get channeling with a false bottom.

 

[Denny]

How old do you think grain has to be to be stale and affect efficiency? The batch I mention above was done with TF Pearl malt as the base malt, bought two and half years ago in a group buy, but freshly milled.

More than a year or so.