Very Low Efficiency. Please Help!

[Gerry_P]

If you're batch sparging it shouldn't matter how fast you drain the mash tun. You should mix the sparge water in really well and then all of the sugars left in the tun will be evenly distributed and dissolved in the water. So as long as you get all of the wort out, it doesn't matter if it comes out fast or slow. That's one of the big advantages of batch sparging.

Maybe you're talking about fly sparging though, in which case the flow rate does matter.

My understanding is that batch sparging should be drained slowly because it allows for more sugars to be extracted from the grain bed as the liquid passes through it on the way out. Or maybe it was to avoid stuck sparges. Idk, I might be wrong but it seemed like a good idea and it didn't cost extra.

Anyway, here's what I did: the previous batch was either "no sparge" or "batch sparged", depending on who you listen to. Mashed, recirculated, didn't drain anything, added hot sparge water, stirred, let settle, and drained pretty fast. It took maybe 10 minutes to drain, maybe a little more, and my brewhouse effciency was 61% (I thought it was 63% but I had confused it with a previous BIAB batch.)

Last batch I had my mash tun almost filled, so I recirculated, then started draining the mash slowly while adding sparge water. I didn't drain the mash down to a level just above the grain bed as you're supposed to do when fly sparging. Eventually all my sparge water was in the mash tun, and I just left it draining slowly. The whole thing took about 30-40 minutes, iirc. I ended up with 73% brewhouse. Idk what you'd call that..."fly batching", "flatch sparging", or maybe "lazy man's fly sparge"... I thought I made it up, but as it turns out this guy beat me to it almost 7 years ago: https://www.homebrewtalk.com/showthread.php?t=75454

 

[MagicMatt]

I thought I made it up, but as it turns out this guy beat me to it almost 7 years ago: https://www.homebrewtalk.com/showthread.php?t=75454

The only "problem" i see with his instructions is the last step, when he says to shut the valve while you refill your sparge bucket. If you close the valve during lautering you'll lose your suction effect and thus the grain you've just worked so hard to compact into a filter bed will tend to unsettle. I used to notice this during my vorlauf, because I would only use 1 vorlauf vessel and thus keep shutting my valve while I dump back into the MLT. Once I switched to 2 containers (and let the valve stay open continuously), no more issues losing the suction/siphon.

 

[Gerry_P]

The only "problem" i see with his instructions is the last step, when he says to shut the valve while you refill your sparge bucket. If you close the valve during lautering you'll lose your suction effect and thus the grain you've just worked so hard to compact into a filter bed will tend to unsettle. I used to notice this during my vorlauf, because I would only use 1 vorlauf vessel and thus keep shutting my valve while I dump back into the MLT. Once I switched to 2 containers (and let the valve stay open continuously), no more issues losing the suction/siphon.

I missed that part, I left mine on during lautering. That's a good idea with the vorlauf though, I'll try that next time. Thanks brah!

 

[doug293cz]

My understanding is that batch sparging should be drained slowly because it allows for more sugars to be extracted from the grain bed as the liquid passes through it on the way out. Or maybe it was to avoid stuck sparges. Idk, I might be wrong but it seemed like a good idea and it didn't cost extra.

This is incorrect. After stirring at the end of the mash, the sugar concentration should be uniform throughout the volume of wort, and in equilibrium with any sugar retained in the grain. Without adding more water, there is nothing you can do to extract any more sugar from the grain, so slow draining does nothing. Again, after adding batch sparge water and stirring sufficiently, the wort and grain are in equilibrium, and no more sugar can be extracted.

Things are completely different for fly sparging. Before sparging begins, sugar in wort and grain are in equilibrium. But, as soon as you add sparge water, things are no longer in equilibrium. You want to use the sparge water to sweep the wort out of the grain bed, and dissolve remaining sugar out of the grain (which can now happen because the sugar concentration in the grain is higher than that in the sparge water.) You want to go slowly for three reasons:

1. Sugar comes out of the grain by diffusion, which takes time. Going slower maximizes the amount of sugar each small volume of sparge water picks up.
2. To avoid channeling where the sparge water bypasses much of the grain bed, so doesn't extract the remaining sugar.
3. To minimize the mixing of the wort and sparge water, as mixing reduces the sugar concentration gradient between the grain and water, thus reducing the rate of diffusion of sugar out of the grain.

The above is just a more detailed explanation of what @peterj said above:

If you're batch sparging it shouldn't matter how fast you drain the mash tun. You should mix the sparge water in really well and then all of the sugars left in the tun will be evenly distributed and dissolved in the water. So as long as you get all of the wort out, it doesn't matter if it comes out fast or slow. That's one of the big advantages of batch sparging.

Maybe you're talking about fly sparging though, in which case the flow rate does matter.

Brew on

 

[Gerry_P]

This is incorrect. After stirring at the end of the mash, the sugar concentration should be uniform throughout the volume of wort, and in equilibrium with any sugar retained in the grain. Without adding more water, there is nothing you can do to extract any more sugar from the grain, so slow draining does nothing.

Thanks for the input. I hear what you're saying, and I'm certainly no (insert type of scientist here). However, consider that once you open the spigot, you are disrupting the state of equilibrium by applying force. The force of the liquid being pulled through the grain bed flushes some of the residual sugars from the grains. I might be using the wrong terminology, but we might be talking about 2 different processes (chemical vs. mechanical maybe? idk.) It shouldn't matter that there are already sugars in the liquid, asssuming you haven't extracted 100% of the sugars from the grains when you stirred in your sparge water. Also I don't know what happens as you approach the saturation point of sugars in the mash, but I don't think that's an issue for most homebrewers.

Edit: I noticed you said that you couldn't extract more sugars unless you add more water. Think what would happen if you used more grain, but the same amount of water. You would get a higher gravity wort, as more sugars have been added. That's not the same thing as saturation point.

Other edit: Never mind previous edit, I see what you're saying.

 

[doug293cz]

Thanks for the input. I hear what you're saying, and I'm certainly no (insert type of scientist here). However, consider that once you open the spigot, you are disrupting the state of equilibrium by applying force. The force of the liquid being pulled through the grain bed acts to flush some of the residual sugars from the grains. I might be using the wrong terminology, but we might be talking about 2 different processes (chemical vs. mechanical maybe? idk.) It shouldn't matter that there are already sugars in the liquid, asssuming you haven't extracted 100% of the sugars from the grains when you stirred in your sparge water. Also I don't know what happens as you approach the saturation point of sugars in the mash, but I don't think that's an issue for most homebrewers.

No, mechanical action will not disrupt a concentration equilibrium. Fluid shear (from flow or stirring) can get you to equilibrium faster, however, if you are not there already. It works by creating steeper concentration gradients by disturbing the natural diffusion gradient. This is why things dissolve faster if you stir.

If the sugar concentration in the grain is higher than that of the wort, then equilibrium has not been reached, and more time will allow more sugar to be extracted. If the concentrations are equal, then nothing you can do mechanically will extract more sugar.

Once you have reached equilibrium, the grain particles contain no more starch, and can be thought of as little sponges. The sugar remaining in the grain is in wort soaked into the sponges.

As you approach saturation, the concentration gradients are reduced, and the rates of diffusion are reduced, so additional sugar goes into solution slower. You are correct that we are no where near saturation in wort at mash temperatures.

Edit: I noticed you said that you couldn't extract more sugars unless you add more water. Think if you used more grain, but the same amount of water. You would get a higher gravity wort, as more sugars have been added. That's not the same as saturation point.

When it's time to sparge, you're past the point of adding more grain, and what I wrote only applies after the mash is complete and run off/sparging begins. The amount of grain mashed does determine the amount of sugar available in the mash.

Brew on

 

[Gerry_P]

No, mechanical action will not disrupt a concentration equilibrium.

Thank you! That does clear things up a bit, especially the part about the sugar in grain being wort that's absorbed after equilibrium is reached. That changes everything. (Well, not "everything", but you know...)

Btw, just for fun I did a little research on batch sparging, and came up with these definitive answers :

- "As with other sparge techniques, you do not want to drain the grain bed too quickly. You need to allow the sparge water to do its work. Drain slowly." - BYO, 1/97
- "Completely drain the mash tun as fast as your system will allow." BYO, 1/04
- "Because you do not have to wait for the water to slowly drain into/out of the mash tun, batch sparging can save you a half hour or more on this step alone." Brew365.com
- "Vorlauf and let it drain SLOW." - Some guy on BA.com
- "Open your tap as much as you are comfortable." Beersmith.com
- "With batch sparging and fly sparging (see below) it is imperative that the liquid is drained slowly." - Homebrewingandbeer.com

 

[Gerry_P]

Mashed, recirculated, didn't drain anything, added hot sparge water, stirred, let settle, and drained pretty fast. It took maybe 10 minutes to drain, maybe a little more, and my brewhouse effciency was 61%

I think it's pretty safe to say that this was a "no sparge" batch (the LHBS guy threw me off by calling it a batch sparge) and that I've never really done a normal batch sparge. The "Flatch sparge" or whatever you want to call it worked pretty well, plus it was fast and easy. We'll see what happens when I do my Belgian pale ale, hopefully tomorrow.

 

[MagicMatt]

I think it's pretty safe to say that this was a "no sparge" batch (the LHBS guy threw me off by calling it a batch sparge) and that I've never really done a normal batch sparge. The "Flatch sparge" or whatever you want to call it worked pretty well, plus it was fast and easy. We'll see what happens when I do my Belgian pale ale, hopefully tomorrow.

It sounds like you only mashed and then did a mash out step. So "no sparge" is correct. You just mashed out. Sparging (either batch or fly) would be any additional H2O added after the mash out.

 

[Gerry_P]

It sounds like you only mashed and then did a mash out step. So "no sparge" is correct. You just mashed out. Sparging (either batch or fly) would be any additional H2O added after the mash out.

Thanks Matt, that explains it. The other day I did my Belgian pale ale the same way (hybrid sparge, not no-sparge) and got 77%, with an OG of 1.059. My last batch with this "technique" was 1.105 and 73%. I'm pretty happy with it so far. (Side note: I used the Wyeast Belgian Ardennes with a starter and had a solid 1/2" of krausen 3 hrs. after pitching. Those little guys work fast!)

Btw, when I said the LHBS guy threw me off I wasn't badmouthing him. The guys at Brewstock are great and I chalked it up to a poor explanation of the process on my part.

 

[MagicMatt]

Btw, when I said the LHBS guy threw me off I wasn't badmouthing him. The guys at Brewstock are great and I chalked it up to a poor explanation of the process on my part.

Yeah they can be helpful but sometimes I feel like I know more than them (and I'm no expert on most of this stuff, though I strive to be!).

One other thing to consider; if you are adding water to bring temperature up, you are throwing off your water/grain ratio which will also have a negative impact on efficiency.

You've been lied to! This is actually inaccurate as I mentioned earlier in this thread (see this post). Thinner mashes can actually help efficiency.

 

[Gavin C]

Yeah I'm having them crushed. They look good to me... most of the grains are in multiple pieces. I'll try to get pic..

Attached. Thoughts?

This cush does not look acceptable. If your BIAB'ing use it to your advantage and crush fine. This is what my crush looks like for comparison. There are no whole kernel left. Some flour present.

My Crush

One other thing you can do with small batches is to place the mash in the oven (if its in a pot) on a hold warm setting. You can monitor the temps with a probe thermometer. My oven can go as low as 145F. It may not be an option. Just thought I'd throw it out there.

 

[doug293cz]

One other thing to consider; if you are adding water to bring temperature up, you are throwing off your water/grain ratio which will also have a negative impact on efficiency.

I don't believe this is true. Can you back it up with something other than opinions and anecdotes? Kai has shown that thinner mashes have higher efficiency in a no sparge situation (http://braukaiser.com/wiki/index.ph...e_infusion_mashing&redirect=no#Mash_thickness.) What happens when you include sparging gets more complex, but a simple statement that "thinner mashes lead to lower efficiency" is misleading at best.

Edit: I see @MagicMatt beat me to this point.

Brew on

 

[Gavin C]

@doug293cz

That is a spam post you replied to. It is an exact cut and paste of an earlier post (3rd or 4th in th thread)

I agree with you. Thin mashes will promote a higher efficiency. This has been well established. They are the norm in no-sparge full volume brewing of course.

 

[peterj]

Dude, for a 1 gallon batch, you should try stovetop BIAB. I think trying 1 g batches with a 10 g cooler may be stretching it.

What's with all this spam?

 

[chubby]

Just a bit of a follow up from the start of this thread....still looking for solution(s).

Summary:

1. 1 gal batch size
2. BIAB - 3 gal cooler to mash in and hold temps, Grain crush is fair, but not perfect
3. Built purified water to Pale profile ranges (see image)
4. 1.5 QT/Lb Grain minimum
5. Mashed for 1 hour 40 minutes
6. Mash temp held at 154
7. Soaked/Dipped grains in 1.25 gal water at 168
8. OG 1.038 (post boil), 1.25 gal, 51.5% Measured efficiency with refractometer.... (see images)

Yes, I am using the gravity scale on the ATC refractometer, but when I plug the Brix % into a calculator I'm getting a result not too far off from the scale. I've calibrated the refractometer with distilled water...I know they're not "made" for Wort, but adjustments can be made. The batch is already fermenting so it would only add complexity to compare to a hydrometer reading at this point. On the next batch I will compare to a hydrometer, which looking back I should have been doing all along. I guess I don't understand how I can verify the calibration and the tool be off this far....IF it is.?.? The refractometer is supposed to have ATC. I'm placing 3 drops on the lens, closing the cover, and waiting at least 30 seconds for the temp to settle. Or is there something still wrong with my process?

Below are some screenshots relevant to this batch.

I'm beyond frustrated at this point.

 

[MadHomebrewer]

Following, I'm also having efficiency issues with one gallon all grain batches in my 2 gallon mash tun.View attachment ImageUploadedByHome Brew1430846322.412988.jpg

 

[chubby]

I added 4 cups of hot water, first 2 and then another 2 to try to bring up the temp a little at the beginning of the mash. I've not found this too effective. The overall temp seems very resistant to increases.

If this water was too hot, could that cause inefficiency problems? Damage enzyme activity? I stirred slightly as I poured it in to keep it from creating hot spots. The overall temp wasn't really affected with each 2 cup addition.

Could this cause a 20% decrease in efficiency?

 

[chubby]

Following, I'm also having efficiency issues with one gallon all grain batches in my 2 gallon mash tun.View attachment 276028

Are you using a hydrometer? What efficiency numbers are you seeing?

 

[MadHomebrewer]

Are you using a hydrometer? What efficiency numbers are you seeing?

I quit using my hydrometer for my one gallon batches and got a refractometer. It was supposed to be a double IPA with a target OG of 1.075, but I ended up with an OG of 1.057. I ended up with an IPA instead, lol.

 

[peterj]

One other thing to consider; if you are adding water to bring temperature up, you are throwing off your water/grain ratio which will also have a negative impact on efficiency.

This was another spam post. Copied from #3 of this thread.

But I think we covered the topic earlier. It's not a problem.

 

[grevengrevs]

Milling my own grains helped my efficiency a lot.

 

[chubby]

I quit using my hydrometer for my one gallon batches and got a refractometer. It was supposed to be a double IPA with a target OG of 1.075, but I ended up with an OG of 1.057. I ended up with an IPA instead, lol.

I'm at a loss. This is my 5th all grain 1 gallon batch. I've made several revisions to equipment and process and nothing has been the cure all. I've done everything I know how from a process standpoint.

-Longer Mash (100 mins)
-Higher Mash Temps (154)
-Built water profile
-Cooler sized for 1 gal batch (3 gal)
-1.5-2 Qts per lb for mash

About the only thing I can figure at this point is my measurements may be off or I screwed up enzyme activity by adding too hot water to try to bring up mash temps a little. I stirred as I added and the temp of mash only reached 154. Crush isn't perfect, but longer mash times should have offset that...

 

[chubby]

Milling my own grains helped my efficiency a lot.

That's about the only dang thing I'm not doing yet. Earlier in the thread I posted a pic of my grain crush. I extended the mash time to 1 hr 40 mins to offset this.

What were your numbers before and after doing your own crush? I'd just like to be around 72% efficiency. 30's to low 50% just seems like I'm doing something wrong....

 

[peterj]

Longer mash times won't offset a bad crush. If you have whole grains in there, letting them soak longer still won't allow the starches to get out and be converted to sugar.

 

[chubby]

Longer mash times won't offset a bad crush. If you have whole grains in there, letting them soak longer still won't allow the starches to get out and be converted to sugar.

Yeah, I had some whole grains still. Someone had made a suggestion to mash longer. I guess I was thinking if the grains were at least cracked a longer mash might help.

I looked at the crusher at the store where I get my supplies. The rollers didn't seem to be adjustable. The bearings on each end were in a solid block of aluminum. I think a credit card would have easily fit through the gap. Next time I'll ask if they can adjust it though. Or maybe run them through twice? I'd like to make sure I'm not the 'problem' before I go asking them to look at their process.

 

[stpug]

Change one variable next time. This time it's "the crush" - nothing else.

Aim for a lowish gravity so the grains cost <$4. Mash as normal. Collect accurate preboil volumes and preboil gravities. If you achieve a reasonable gravity then continue on with your brewday. If you fall well short of your preboil gravity then scrap this batch and cut your brewday short (save your effort, time, and hops for next batch); then look at another variable to change on your next batch.

As for the crush, have your LHBS run it through twice for you. Then come home and run it through your blender at 1/4-1/2 lb increments using a pulsing just to ensure you really break it down and end up with fairly small pieces and flour (your grainbag should contain most of it, so no worries). See how this works out in terms of gravity.

As for doughing in, get your strike water where it needs to be and pour your grain into it while stirring (greenbay rackers calculator works exceptionally well). With only a pound or two of grain this should take no more than 10 seconds to get all of the grain in there. Stir it up well and check your mash temp. If you're a little high or a little low, no worries, that can be fixed on future batches because this batch is about reasonable efficiency.

 

[chubby]

Change one variable next time. This time it's "the crush" - nothing else.

Aim for a lowish gravity so the grains cost <$4. Mash as normal. Collect accurate preboil volumes and preboil gravities. If you achieve a reasonable gravity then continue on with your brewday. If you fall well short of your preboil gravity then scrap this batch and cut your brewday short (save your effort, time, and hops for next batch); then look at another variable to change on your next batch.

As for the crush, have your LHBS run it through twice for you. Then come home and run it through your blender at 1/4-1/2 lb increments using a pulsing just to ensure you really break it down and end up with fairly small pieces and flour (your grainbag should contain most of it, so no worries). See how this works out in terms of gravity.

As for doughing in, get your strike water where it needs to be and pour your grain into it while stirring (greenbay rackers calculator works exceptionally well). With only a pound or two of grain this should take no more than 10 seconds to get all of the grain in there. Stir it up well and check your mash temp. If you're a little high or a little low, no worries, that can be fixed on future batches because this batch is about reasonable efficiency.

Thanks! I have enough of these grains for 2 more 1 gallon batches....more if I lower the gravity target. Guess I can treat them to the blender since I've already left the store...I'll make sure the 'crush' is improved.

That's a great idea not to waste hops and yeast if I don't hit my pre-boil targets.

 

[stpug]

That's a great idea not to waste hops and yeast if I don't hit my pre-boil targets.

I see it that way. In your case, due to frustration, I would just want to determine the culprit quickly. Take it one step at a time. The sugars (i.e. efficiency) come from the grain so there's no point moving beyond a mash and sparge if you're not getting your sugar you expect (deserve ). At about $4 a test, it's worth trying five or so tests to figure it out.

 

[jtratcliff]

It's your crush.... Double or triple crush at the LHBS. Barring that (my LHBS forbids double crush, for instance... Just one of the many reasons I shop online whenever possible) put it in the blender or hit it with a rolling pin... With BIAB there is no worry about a stuck sparge.

You want ALL the kernels broken... A little flour is no problem.

Single biggest efficiency improvement I got came from my ugly-junk corona mill.

 

[stpug]

^^Troll, and there would not be a negative impact on efficiency due to water/grain ratio.

 

[Brew_G]

^^Troll, and there would not be a negative impact on efficiency due to water/grain ratio.

^^Troll

 

[chubby]

So I picked up a mill. The rollers are spaced so that credit card just squeezes through them without being crushed. I know that's not very technical, but I understand a typical credit card is around .030.

I ran a batch of grains through that were crushed by the store. There seemed to be no remaining whole pieces. I honestly think it seems like a good setting. Not too large and I'm hoping not too fine. I am doing BIAB for these batches, but I need to make it work for 5 gallon batches or larger in the future.

I'm attaching a picture of my second crush vs. the original crush from the store. The Vienna (smaller bag on top) is the crush from the store. The bottom bag was crushed by them and then a second time by my mill.

Thoughts? I'm targeting this weekend to test this variable change.

 

[doug293cz]

So I picked up a mill. The rollers are spaced so that credit card just squeezes through them without being crushed. I know that's not very technical, but I understand a typical credit card is around .030.

I ran a batch of grains through that were crushed by the store. There seemed to be no remaining whole pieces. I honestly think it seems like a good setting. Not too large and I'm hoping not too fine. I am doing BIAB for these batches, but I need to make it work for 5 gallon batches or larger in the future.

I'm attaching a picture of my second crush vs. the original crush from the store. The Vienna (smaller bag on top) is the crush from the store. The bottom bag was crushed by them and then a second time by my mill.

Thoughts? I'm targeting this weekend to test this variable change.

The two pass crush looks a lot better. You should get a significant efficiency boost with that crush.

A 0.030" mill gap will not cause any problems for BIAB. I do 5 gal BIAB batches with my mill gap set to 0.016" without any draining issues. There are others who grind even finer (coarse flour) with good results (although they do have to reduce their mash times to compensate for the faster saccharification.)

Brew on

 

[chubby]

Thank you for all the input.

It was the crush....

My efficiency came up to 72.6%.

My gap on my mill is .030. If I decrease the gap am I likely to see a higher efficiency? I am doing BIAB.

I'm okay with my numbers, but I'm more okay having the highest utilization possible with my system so I can use less grains.

 

[doug293cz]

Thank you for all the input.

It was the crush....

My efficiency came up to 72.6%.

My gap on my mill is .030. If I decrease the gap am I likely to see a higher efficiency? I am doing BIAB.

I'm okay with my numbers, but I'm more okay having the highest utilization possible with my system so I can use less grains.

I BIAB and have my mill gap set at 0.016". I get efficiencies in the low to mid 80's.

Edit: So many threads, can't remember what I said where.
Brew on

 

[chubby]

I still don't think I've whipped this utilization thing.

I made the exact same recipe again this weekend.

crushed my grains at .016.
I built my water.
1.5 qts per pound.
Hit my mash temp of 154 and held it by 1 degree.
Mashed for 1 hour.

For the first time I did an iodine test on this batch. at 50 minutes all of the starches appeared to be converted.

The difference between this batch and the last that I had success with was 90 minutes last time and 60 this time. I don't understand how that could be a factor if the starches were converted in 60 minutes. It is a Pilsner base, but the crush is pretty fine.

My utilization was 66% (down from 72% on the last batch). I was expecting an increase in utilization with the finer crush. I'm doing BIAB and washing the grains in a gallon of 169 degree water after the initial mash. They soaked for about 15 minutes the second time.

Thoughts?

 

[Gavin C]

...
1.5 qts per pound.

...

With BIAB, don't concern yourself with targeting a water to grain ratio. Mash with as much of your total water volume your pot will allow. A finer grist and large mash volumes (with appropriate pH corrections) will equate to better efficiencies.

This is too little water for a BIAB mash in my view.

I mash with the entire volume and do no sparge as my pot size allows this.

Last brew with an 85% pilsner grainbill was 9lbs of grain and 7.9 gallons of water at strike. (3.51qts/lb)

 

[chubby]

Mash with as much of your total water volume your pot will allow.

I'm doing 1 gallon batch size in a 3 gallon igloo water cooler. I can fit the entire 2.25 pre-boil volume with grains in there I'm sure.

You don't do a sparge/rinsing of the grains. Do you do any stirring during the mash or dunk the grains? What kind of efficiencies are your seeing?

I'm curious why my results were different this time. I took my samples FOR IODINE TEST from the valve on the front of the cooler. I assume the action is fairly uniform throughout.

I don't have a PH meter as you do. I have some PH strips, but they are the broad range ones. The colors indicated that the mash PH was somewhere between 5 and 6. From that, I'm assuming that PH isn't my problem.

 

[Gavin C]

I'm doing 1 gallon batch size in a 3 gallon igloo water cooler. I can fit the entire 2.25 pre-boil volume with grains in there I'm sure.

You don't do a sparge/rinsing of the grains. Do you do any stirring during the mash or dunk the grains? What kind of efficiencies are your seeing?

I'm curious why my results were different this time. I took my samples FOR IODINE TEST from the valve on the front of the cooler. I assume the action is fairly uniform throughout.

I don't have a PH meter as you do. I have some PH strips, but they are the broad range ones. The colors indicated that the mash PH was somewhere between 5 and 6. From that, I'm assuming that PH isn't my problem.

I would absolutely recommend a full voulme mash with a fine milling of the grain with your MIAB method. Squeeze the snot out of the bag. I lose less than 0.05gallons per pound to grain absorption and do not sparge.

On the pH issue. Forget the strips. The experts on HBT say they are worse than useless. You are better served using Bru'n water and working blind. It is a great tool. Very accurate predictions of mash pH. Not spot on, but very close. Get a water report from your city or Ward labs and put the data into Bru'nWater. Each brew work out any water additions and the mash pH based on the grist. I adjust pH with acid malt. (usually 2-5% of the grain-bill).

Without some sort of water report, do nothing to the water. No mineral additions, no pH adjustments. Other option is to use RO water for each batch. A blank canvas to work with. No report needed, trust the software and do mineral and pH adjustments blind.

My efficiency will hover around 80%. I formulate my recipes at 80% brewhouse efficiency. I will lower it for bigger grain bills to 75% and up it to 82% for lighter grain-bills. An 80% setting allows me some wiggle room. My efficiency this weekend was a little lower than usual. I tried a new mashing technique (step mash with BIAB) and my Brewhouse efficiency was 78%, (planned 80%). Mash efficiency was 89%.

OG was 1.046 Planned OG was 1.047 so no major effect on the finished wort with the parameters (gravity, IBU and color) still well within the style I was looking for.

9lbs of grain for a 5.5 gallon batch at 1.046

Hope that helps