Incredibly Frustrated With Poor Efficiency

[Monmouth00]

I'm back with the same darn problem. I'm getting poor efficiency, and not hitting my targets. I'm four brews into my new eBIAB system and I cannot figure out what I'm doing wrong. Can you please help me identify the problem?

Mosaic Blonde recipe looks like this:
10 Lbs. Golden Promise, 8 oz. White Wheat, 4 oz Special B, 4 oz Acid Malt. Fine Crush from LHBS
.5 oz Hellertauer Blanc (60 min) 1 oz Mosaic (5 min) 1.5 oz Mosaic (whirlpool)
Built my water with a balance yellow profile, estimated 5.38 pH (Bru 'n Water)
152 degree mash temp for 60 min. Boil for 60 min.
Pitched 2 packets US-05 - fermented 7 days at 68 degrees. 24 Hour diacetyl rest at 72 degrees.

Measured this:
Post mash gravity: 9.4 Brix
Boil volume: 8.05 Gallons
Post boil gravity: 12.2 Brix
Post boil Vol: 6.47 gallons
Final Gravity: 6.2 Brix (1.04 correction factor)
ABV: 5.01%

Beersmith says my measured efficiency is 62.5% - and I'm off my ABV target by almost a full 1%

I'm guessing it's something in my process, but I can't identify it. I didn't recirculate during the mash this time - not until the very end at least. I set it at 152, kept it covered, and let the inkbird control it for the 60 minutes. The kettle is well insulated. Stirred well at 60 minutes, recirculated for 5-10 minutes, then pulled the bag. The bag was drained and squeezed thoroughly, and everything was added back into the boil kettle.

I'm feeling like my boil volume is off, and maybe that's diluting the beer?
I noticed again that (even thought the inkbird was set to 152) the top of the mash was only about 149-150 degrees. I was hoping nor recirculating would solve that problem, but it didn't. Could that be the culprit?

Please help. Yeah, it's beer and it'll drink, but I want it to be better.

Can you help me identify what might be going wrong?

Thanks,

Monmouth00

 

[BrewZer]

How fine is your LHBS's mill set? I'm guessing here but maybe not down as far as you can get.

Is your grist chunky or sandy?

 

[Monmouth00]

How fine is your LHBS's mill set? I'm guessing here but maybe not down as far as you can get.

Is your grist chunky or sandy?

From what I can tell, the crush isn't the problem. My LHBS owner is a frequent contributor to this forum and a sponsor, so I trust his mill settings are appropriate for my BIAB setup.

 

[cubalz]

Have you measured your boil off rate? BeerSmith is completely dependent on having your equipment set up done correctly with no guess work. Otherwise you are flying blind with what your numbers should be.

 

[Monmouth00]

Have you measured your boil off rate? BeerSmith is completely dependent on having your equipment set up done correctly with no guess work. Otherwise you are flying blind with what your numbers should be.

My pre-boil volume was 8.05 and post boil was 6.47 gallons. So I have a boil off rate of approximately 1.5 gallons, right?
I'll make sure this is reflected in my profile, but how much does this really effect efficiency?

 

[BrewZer]

From what I can tell, the crush isn't the problem. My LHBS owner is a frequent contributor to this forum and a sponsor, so I trust his mill settings are appropriate for my BIAB setup.

Maybe he can help you, then. You should summon him directly.

 

[RM-MN]

From what I can tell, the crush isn't the problem. My LHBS owner is a frequent contributor to this forum and a sponsor, so I trust his mill settings are appropriate for my BIAB setup.

The only one I trust to do the proper milling for my BIAB is myself. All others are suspect. For $23 you can get a mill and set it yourself.

https://www.ebay.com/itm/3818924662...V5y4WuKy9IF-OF8DUUIs-syTBAWe7JwwaAmV1EALw_wcB

 

[tracer bullet]

Random thoughts -

1) Plug your info into an online calculator, i.e. brewer's friend. Get your grain bill and pre-boil water volumes correct. Then play with the efficiency # until the expected pre-boil gravity matches what you read. See what that efficiency # is.

2) Make sure you are reading correctly. Calibrate your refractometer and / or hydrometer w/ some distilled or R.O. water. It's a bit late now but next time use both measurement devices and make sure they agree with each other.

3) Consider that you are where you should be for your method. BIAB no-sparge is often cited as being 60 - 65% efficient. If you want more, you're going to have to develop a sparge process. Think of it as rinsing the grain to get extra sugars out of it. It doesn't have to be a complicated process. For my Anvil setup I've been using indoors over the winter I squeeze the bag, move it to an old pot w/ room temp sparge water, massage it a little, squeeze again and then dump it into my boil kettle. It's not much extra work, I end up using the same amount of water, and I'm doing it while it's coming up to a boil so the brew day length doesn't get any longer either.

 

[BrewChatter]

I agree with Tracer Bullet. If you want to get more out of BIAB, you'll want to mash with 1.2 - 1.5 qts per pound of grain, and soak/sparge in a separate vessel. This will help you nail your pH in the mash, which will help to maximize the effectiveness of the enzyme and increase efficiency. If you don't want to do it that way, you can try some Five Star 5.2, or just calculate extra base grain into your grain bill.

 

[Monmouth00]

Random thoughts -

1) Plug your info into an online calculator, i.e. brewer's friend. Get your grain bill and pre-boil water volumes correct. Then play with the efficiency # until the expected pre-boil gravity matches what you read. See what that efficiency # is.

2) Make sure you are reading correctly. Calibrate your refractometer and / or hydrometer w/ some distilled or R.O. water. It's a bit late now but next time use both measurement devices and make sure they agree with each other.

3) Consider that you are where you should be for your method. BIAB no-sparge is often cited as being 60 - 65% efficient. If you want more, you're going to have to develop a sparge process. Think of it as rinsing the grain to get extra sugars out of it. It doesn't have to be a complicated process. For my Anvil setup I've been using indoors over the winter I squeeze the bag, move it to an old pot w/ room temp sparge water, massage it a little, squeeze again and then dump it into my boil kettle. It's not much extra work, I end up using the same amount of water, and I'm doing it while it's coming up to a boil so the brew day length doesn't get any longer either.

Really?
I though normal BIAB efficiencies were closer to 75-80% even without sparging?
Isn't that one of the benefits of a very fine crush?

 

[Immocles]

Really?
I though normal BIAB efficiencies were closer to 75-80% even without sparging?
Isn't that one of the benefits of a very fine crush?

I get 70-72% on full volume. For several brews in a row I was at that low 60s. I tightened my corona mill a twitch and it shot back up into the low 70s.

 

[Upstate12866]

Tracer bullet seems to have the right idea. I posted here about very bad efficiencies like you, sometimes sub 60% Biab.

I now grind to flour in a blender, squeeze, then dunk in warm water and squeeze again. This has brought me to the 70-75% range, occasionally higher. I usually calculate the recipe for 75% then I can always add sugar or lme if I come up short. However I get a lot of trub with this method (not a big deal though).

 

[doug293cz]

My pre-boil volume was 8.05 and post boil was 6.47 gallons. So I have a boil off rate of approximately 1.5 gallons, right?
I'll make sure this is reflected in my profile, but how much does this really effect efficiency?

Boil off has very little effect on efficiency, and no effect after the mash. Higher boil off means you need to start with more strike volume, which gives a slight increase in lauter efficiency (one of the components of mash efficiency.)

What was your strike water volume? With that and the data in the first post we can calculate your conversion and lauter efficiencies, and that should point to where the problem is.

Brew on

 

[codysorgenfrey]

I don’t BIAB, but I had similar frustrations at first with low mash efficiency. I tried everything, until I finally got a mill and made sure the grind was what it should be and my mash efficiency shot way up, like 15% consistently.

If you’re not milling the grain so you can stick your hand under the mill and see how much “flour” vs chunks it’s making it can be hard to know if it’s right. Getting the milled grist handed to you makes it difficult to tell.

 

[Monmouth00]

Boil off has very little effect on efficiency, and no effect after the mash. Higher boil off means you need to start with more strike volume, which gives a slight increase in lauter efficiency (one of the components of mash efficiency.)

What was your strike water volume? With that and the data in the first post we can calculate your conversion and lauter efficiencies, and that should point to where the problem is.

Brew on

Strike water volume was about 8.5 gallons. Maybe a hair less.

 

[naptowndon]

I had issues with my first few brews using recipes and beersmith for BIAB. I found that converting all grain to BIAB and recipes called to start with too much water. Lower your starting water and pay attention to volume in fermenter. My efficiency into fermenter went back into 90+

 

[wilserbrewer]

What’s your volume under the FB?
Total mash volume?

 

[Qhrumphf]

BeerSmith defaults to "brewhouse efficiency", ie efficiency to the fermenter, which is a REALLY poor metric to plan recipes around since it's highly recipe dependent. It is easily the dumbest aspect of that entire program. Hop heavy beers will have lower overall efficiency than low-hop beers, even with the exact same grain bill and process, due to absorption from hop matter. If you don't leave em behind in the kettle and sacrifice to brewhouse efficiency, you'll still leave em behind when racking for packaged efficiency. But it doesn't effect your gravity and it's a stupid metric to plan a recipe around.

You should do all your efficiency measurements based on what actually makes it into the kettle where it actually impacts your gravity, not the fermenter. In BeerSmith you can trick the program into doing this by defaulting all your kettle losses in your equipment profile to zero such that it treats your actual postboil volume as your batch volume.

Now, this may not be the issue in your case. But as said above, BeerSmith needs all equipment settings right or it spits out garbage.

Crush I'd still say is your most likely culprit.

Even then you shouldn't have to crush to flour. But I've never ever seen a worthwhile store crush for any brewing style. From any source. Maybe your source is different, but I'll believe it when I see it.

 

[doug293cz]

Strike water volume was about 8.5 gallons. Maybe a hair less.

Ok, I calculate your mash efficiency as 74%. Your brewhouse efficiency will be lower than that by the ratio of Fermenter_Volume / Post-Boil_Volume.

I get your coversion efficiency as 83% - 84%, which is quite low. Conv eff should be 95% or higher. Biggest factors in conversion efficiency are crush and mash time.

Your lauter efficiency is about 89%, which is quite good. This high, no-sparge, lauter efficiency is the result of your very low grain absorption rate (0.041 gal/lb), which is achieved with aggressive squeezing.

Raising your conversion efficiency to 95% would bring your mash efficiency up to ~84%, and 100% conversion would bring your mash efficiency up to ~88%

Brew on

 

[Monmouth00]

What’s your volume under the FB?
Total mash volume?

I think it’s right at about 3 gallons under the false bottom.
I aim for my strike temp to be about 158, and my grains sit at 68 deg room temp for at least 24 hours before mashing.
My pre-mash water volume is about 8.5 gallons.
I use both a hop spider and hop bags, so the total volume of post boil goes into the fermenter.

 

[bracconiere]

for a post boil of 12.2 brix, beersmith tells me that's 1.048 or 80% effec? (lol, if you want to bump that pretty good number allready, to my awesome level....try a 30min mash at your mash temp, then a second half hour at 162f...then you'd pull 1.057 off that grain bill. but that's just me )

 

[Monmouth00]

Ok, I calculate your mash efficiency as 74%. Your brewhouse efficiency will be lower than that by the ratio of Fermenter_Volume / Post-Boil_Volume.

I get your coversion efficiency as 83% - 84%, which is quite low. Conv eff should be 95% or higher. Biggest factors in conversion efficiency are crush and mash time.

Your lauter efficiency is about 89%, which is quite good. This high, no-sparge, lauter efficiency is the result of your very low grain absorption rate (0.041 gal/lb), which is achieved with aggressive squeezing.

Raising your conversion efficiency to 95% would bring your mash efficiency up to ~84%, and 100% conversion would bring your mash efficiency up to ~88%

Brew on

Wow! Thanks so much for all this.
So, without changing the crush- since I don’t have a mill and don’t control it- can I get higher efficiency by increasing to a 90 minute mash?
I though most of the conversion happens in the first 25 minutes. Would I really gain more by mashing longer?

 

[doug293cz]

Wow! Thanks so much for all this.
So, without changing the crush- since I don’t have a mill and don’t control it- can I get higher efficiency by increasing to a 90 minute mash?
I though most of the conversion happens in the first 25 minutes. Would I really gain more by mashing longer?

The rate of conversion is highly dependent on the grit size. Flour can convert in 5 - 10 minutes. Large grits take considerably longer.

The rate limiting step in conversion is the gelatinization of the starch, which starts at the surface of the grits, and proceeds towards the center. The larger the grits, the longer they take to completely gelatinize. You can’t have complete conversion until you have complete gelatinization.

Yes, extending the mash time should increase the conversion percentage. This is the best thing you can do, if you can’t reduce your crush size.

Brew on

 

[tracer bullet]

I though normal BIAB efficiencies were closer to 75-80% even without sparging?

As someone else mentioned, it doesn't have to be, but it's quite commonly seen here. I hit 75% in my Anvil with some sparging, and 85% or so in my propane setup with some serious sparging.

I think it’s right at about 3 gallons under the false bottom.

Maybe, but sounds like a lot. You might want to check on that. Do the 1.25 - 1.50 qts per pound thing, but then add the dead space underneath in addition to it, to make sure you're staying in the right range and not accidentally going a lot lower leaving the grains fairly dry because all the water is under them. Your dead space normally would be around a gallon or less.

I aim for my strike temp to be about 158, and my grains sit at 68 deg room temp for at least 24 hours before mashing.
My pre-mash water volume is about 8.5 gallons.

Use a calculator, there are many online, it's basically balancing the mass and temp of the water to the mass and temp of the grains. There's really no one-size-fits-all. It may turn out 158 is the perfect strike temp but have a look. If you end up too cold your efficiency won't be great.

None of this may be the culprit, I agree it's likely the crush size, but check into them.

 

[Monmouth00]

I’m driving myself crazy between all the calculations, and I’m not really even sure I’m using each one correctly. Between Beersmith, Bru ‘n Water, Brewers Friend, and others that have been recommended, I don’t know which numbers to trust.
Frankly, it’s taking a bit of the enjoyment out of the process, because I’m perpetually disappointed when the actual numbers are so far off from the calculations.
But one thing I do know is that Beersmith is pissing me off by not saving the numbers I put in. It defaults back every time I close the recipe.

 

[bracconiere]

The rate limiting step in conversion is the gelatinization of the starch,

i think this is on topic. do you think it's the extra alpha activity, or better geling, that explains why i get 83% effec with a single 145-158 mash, but if i do a second step at 162f, i get 88-92%?

 

[doug293cz]

i think this is on topic. do you think it's the extra alpha activity, or better geling, that explains why i get 83% effec with a single 145-158 mash, but if i do a second step at 162f, i get 88-92%?

Additional gelatinization.

Brew on

 

[bracconiere]

Additional gelatinization.

Brew on

i've heard basic solutions help with geling too, for like pretzles and stuff....think if when i hit it with my 162f second step, added a bit of food grade lye i'd be able to pull 98%? lol

 

[doug293cz]

i've heard basic solutions help with geling too, for like pretzles and stuff....think if when i hit it with my 162f second step, added a bit of food grade lye i'd be able to pull 98%? lol

No. Raising the pH of the mash is not good for the enzymes, and it can lead to tannin extraction.

You can get conversion efficiency to 100% with crush and time. You can never get lauter efficiency to 100%. Once your conversion efficiency is 100%, the only thing you can do to raise your mash efficiency is to increase the lauter efficiency. You can raise lauter efficiency by squeezing and/or sparging more aggressively. 98% lauter efficiency (and thus 98% mash efficiency) might be achievable with a filter press (an Industrial piece of equipment that uses pneumatic or hydraulic pressure to squeeze the wet grain.)

Brew on

 

[tracer bullet]

I'm a fan of brewer's friend, have no reason not to trust it. When I type in your recipe I see an efficiency in the mid 70's. Not bad.

And thinking about it, 11 pounds of grain giving you 6 and a half gallons of 5% beer isn't bad at all. For a no-sparge process I'd say, off the top, that's almost impressive.

Also noted the conversion factor, so you're using a refractometer. It should be about right but this is a good spot for a hydrometer if you want to be sure.

 

[bracconiere]

(and thus 98% mash efficiency) might be achievable with a filter press (an Industrial piece of equipment that uses pneumatic or hydraulic pressure to squeeze the wet grain.)

damn, lol. i allready tried the squezzing with a bucket lid in my round 10 gallon cooler with 30lb's or so of weights on top of it. i guess to get 98%, i'd need a bigger pot and boil longer (but damn, i can imagine all the things i'd do with that 2 cents a drink i'd be saving! )

 

[Upstate12866]

Some folks are mentioning different temperature steps. My understanding is you can get extra efficiency by working through temperatures in a "step mash." There are enzymes that work at different temps, and while there is overlap (152 or thereabouts), high temps destroy the enzymes that work a bit cooler. In practical terms, this means some ppl mash around 152 or whatever, then "mash out" around 160 for a moment. This might get you a tad more goodies. Keep in mind that I think this means a thinner beer with less residual sweetness since all the complex starches and sugars have been broken into simpler sugars and then into alcohol by the yeast. Definitely worth a google if you haven't checked that out yet.

 

[Monmouth00]

I'm a fan of brewer's friend, have no reason not to trust it. When I type in your recipe I see an efficiency in the mid 70's. Not bad.

And thinking about it, 11 pounds of grain giving you 6 and a half gallons of 5% beer isn't bad at all. For a no-sparge process I'd say, off the top, that's almost impressive.

Also noted the conversion factor, so you're using a refractometer. It should be about right but this is a good spot for a hydrometer if you want to be sure.

I’m getting very different numbers in Beersmith, and am beginning to get very frustrated with it. I like it for building recipes, but there are so many inputs that dramatically alter the calculations. Again, I’m sure I’m not using it correctly and haven’t built my profile correctly, so it’s partially my fault.
I am likely going to switch over to using just Bru ‘n Water to build a base with distilled water, and relying exclusively on Brewer’s Friend for the rest. It’s the most comprehensive site I’ve found. I think I’m getting in trouble switching between the two softwares.
And, point noted with the hydrometer. I’ll start backing up measurements with that next time around. Switched to the refractometer to simplify, but the calculations seem like another spot for errors.

 

[doug293cz]

Some folks are mentioning different temperature steps. My understanding is you can get extra efficiency by working through temperatures in a "step mash." There are enzymes that work at different temps, and while there is overlap (152 or thereabouts), high temps destroy the enzymes that work a bit cooler. In practical terms, this means some ppl mash around 152 or whatever, then "mash out" around 160 for a moment. This might get you a tad more goodies. Keep in mind that I think this means a thinner beer with less residual sweetness since all the complex starches and sugars have been broken into simpler sugars and then into alcohol by the yeast. Definitely worth a google if you haven't checked that out yet.

The amylase enzymes work over a much wider temperature range than people think. Remember that in seed germination and early growth, the enzymes work at room temperature or lower. It’s just that they work much faster at higher temperatures.

The graphs that show peaks in enzyme activity vs. temperature, that people love to show, tell a distorted story. If the enzymes didn’t denature at higher temperatures, the activity would continue to increase as temperatures increased. The activity at higher temperatures starts to drop off because the enzymes start denaturing faster than they work. Fewer enzymes working at a faster rate eventually results in reduced activity.

The main reason people see efficiency improvements is that the longer total dwell time for a step mash vs. single infusion mash gives more time for more gelatinization to occur. Similar thing for mash out increasing efficiency. The higher temp boosts gelatinization rate, and if there are still active enzymes, then you get more conversion. If you run a single temp infusion long enough to get 100% conversion, then neither a step mash, nor a mash out would give an increase in efficiency.

Neither beta amylase, nor alpha amylase can break the branching bonds in amylopectin, so neither of them can convert the limit dextrins that remain in the wort. The only enzyme in malt that can reduce the final level of limit dextrins in the wort is Limit Dextrinase, which can break the branching bonds in in amylopectin. The most efficient temperature for limit dextrinase is slightly below that of beta amylase. So, it is really the limit dextrinase that is responsible for the higher fermentability of lower temp mashed wort, not beta amylase. Alpha amylase alone can create 100% fermentable sugars from linear (non-branched) starch chains, given enough time - no beta amylase is required. This is a common misunderstanding.

There is another enzyme - amyloglucosidase (aka gluco amylase) - not present in normal malts, that can also break down limit dextrins in wort or beer. This is typically added during mashing and/or fermentation when making brut (fully dry) beers.

Limit dextrins are fragments, remaining from the conversion of amylopectin, that consist of a branching bond with three short chain sugars emanating from the bond. The chains are short enough that the alpha and beta amylase cannot break the linear bonds because the branch blocks the enzyme from getting close enough to the linear bonds.

Brew on

 

[Upstate12866]

The amylase enzymes work over a much wider temperature range than people think. Remember that in seed germination and early growth, the enzymes work at room temperature or lower. It’s just that they work much faster at higher temperatures.

The graphs that show peaks in enzyme activity vs. temperature, that people love to show, tell a distorted story. If the enzymes didn’t denature at higher temperatures, the activity would continue to increase as temperatures increased. The activity at higher temperatures starts to drop off because the enzymes start denaturing faster than they work. Fewer enzymes working at a faster rate eventually results in reduced activity.

The main reason people see efficiency improvements is that the longer total dwell time for a step mash vs. single infusion mash gives more time for more gelatinization to occur. Similar thing for mash out increasing efficiency. The higher temp boosts gelatinization rate, and if there are still active enzymes, then you get more conversion. If you run a single temp infusion long enough to get 100% conversion, then neither a step mash, nor a mash out would give an increase in efficiency.

Neither beta amylase, nor alpha amylase can break the branching bonds in amylopectin, so neither of them can convert the limit dextrins that remain in the wort. The only enzyme in malt that can reduce the final level of limit dextrins in the wort is Limit Dextrinase, which can break the branching bonds in in amylopectin. The most efficient temperature for limit dextrinase is slightly below that of beta amylase. So, it is really the limit dextrinase that is responsible for the higher fermentability of lower temp mashed wort, not beta amylase. Alpha amylase alone can create 100% fermentable sugars from linear (non-branched) starch chains, given enough time - no beta amylase is required. This is a common misunderstanding.

There is another enzyme - amyloglucosidase (aka gluco amylase) - not present in normal malts, that can also break down limit dextrins in wort or beer. This is typically added during mashing and/or fermentation when making brut (fully dry) beers.

Limit dextrins are fragments, remaining from the conversion of amylopectin, that consist of a branching bond with three short chain sugars emanating from the bond. The chains are short enough that the alpha and beta amylase cannot break the linear bonds because the branch blocks the enzyme from getting close enough to the linear bonds.

Brew on

I wish I could like that comment twice!

 

[bruce_the_loon]

I’m driving myself crazy between all the calculations, and I’m not really even sure I’m using each one correctly. Between Beersmith, Bru ‘n Water, Brewers Friend, and others that have been recommended, I don’t know which numbers to trust.
Frankly, it’s taking a bit of the enjoyment out of the process, because I’m perpetually disappointed when the actual numbers are so far off from the calculations.
But one thing I do know is that Beersmith is pissing me off by not saving the numbers I put in. It defaults back every time I close the recipe.

About the Beersmith issue, did you either copy an existing cloud recipe to a different folder or create your own? I have a separate local folder for my recipes in Beersmith and don't use the cloud functions at all. It could be a cloud synchronization issue.

Also, what happens if you explicitly save with the Save button on the far right side between the ? and Save As buttons? Does that work? I've tested and mine auto-saves when I close the program, but I don't remember if that was something I had to set.

 

[Monmouth00]

About the Beersmith issue, did you either copy an existing cloud recipe to a different folder or create your own? I have a separate local folder for my recipes in Beersmith and don't use the cloud functions at all. It could be a cloud synchronization issue.

Also, what happens if you explicitly save with the Save button on the far right side between the ? and Save As buttons? Does that work? I've tested and mine auto-saves when I close the program, but I don't remember if that was something I had to set.

I’m using Beersmith mobile 3 on a tablet. I’m referring specifically to the brew day inputs tab, which never seem to save consistently when I click save. They sometimes revert to the yellow default inputs when I save out and go back in, sometimes they don’t.

 

[FlabbyRoach]

I just brewed NEIPA and got 74% with a recipe in brewers friend. Hit starting OG on the money but I did mill my own grains. Maybe try double mill from LHBS

 

[jerrylotto]

I want to second the step mash suggestion. Maybe try 30 min at 145, 30 at 155, 10 at 165?

 

[madscientist451]

I'm back with the same darn problem. I'm getting poor efficiency, and not hitting my targets. I

Mosaic Blonde recipe looks like this:
10 Lbs. Golden Promise, 8 oz. White Wheat, 4 oz Special B, 4 oz Acid Malt. Fine Crush from LHBS


Measured this:
Post mash gravity: 9.4 Brix
Boil volume: 8.05 Gallons
Post boil gravity: 12.2 Brix
Post boil Vol: 6.47 gallons
Final Gravity: 6.2 Brix (1.04 correction factor)
ABV: 5.01%



Can you help me identify what might be going wrong?

Thanks,

Monmouth00

I put your numbers into the Brewer's friend Brewhouse efficiency calculator and it shows 79.83 % efficiency. Isn't that good enough?
Am I looking at the numbers wrong?
The Boil volume was 8.0 gallons and the Post boil was 6.47 of 5% ABV beer. If you re-brew and use one gallon less water, you will end up with a higher ABV since you will have only 5.5 gallons of beer at the end.
This seems like a pretty simple solution to the OP's problem to me; Am I right or wrong on this?