~76% eff into boiler, ~65% out of boiler?

[cyberbackpacker]

Brewed up 3 batches this weekend, but had an issue with my last batch. (RECIPE and mash schedule is at end of post)

I first decided to do only a 2.5 g batch as I was out of fermenters except for my one gallon Rossi jugs. So I scaled the recipe in beersmith down to a 2.5 gallon batch size.

I used my corona mill for the first time on this batch, but compared to a crush I had from Northern Brewer (side to side comparison) I had a nice crush without any shredding of husks.

Hit all my temps, and on sparging I collected 4.25 gallons of 1.030 wort (est OG was 1.042)

After the boil I collected about 2 3/5 gallons of 1.042 wort (est OG was 1.050).

So I cannot figure out what went wrong on this batch why numbers were so far off... I am fine having a "weaker" session beer, but I want to know so I can better dial in my setup.

My first thought is I may have actually measured out my grains wrong and had mashed less grain than called for.

Second thought is that maybe my thermometer is off, so I was mashing outside of my desired range.

Hydrometer was verified with distilled water, and samples were measured at calibration temperature of 68F.


Recipe: Buffalo Valley Brown Ale- Half Batch 60 minute boil
Brewer: Kevin Hilgert
Asst Brewer:
Style: American Brown Ale
TYPE: All Grain
Taste: (35.0)

Recipe Specifications
--------------------------
Batch Size: 2.50 gal
Boil Size: 3.57 gal
Estimated OG: 1.050 SG
Estimated Color: 22.0 SRM
Estimated IBU: 29.6 IBU
Brewhouse Efficiency: 75.00 %
Boil Time: 60 Minutes

Ingredients:
------------
Amount Item Type % or IBU
3.25 lb Pale Malt, Maris Otter (3.0 SRM) Grain 72.22 %
0.38 lb Pale Malt, Maris Otter (3.0 SRM) Grain 8.33 %
0.25 lb Biscuit Malt (23.0 SRM) Grain 5.56 %
0.25 lb Caramalt (33.5 SRM) Grain 5.56 %
0.13 lb Chocolate Malt (350.0 SRM) Grain 2.78 %
0.13 lb Chocolate Malt (450.0 SRM) Grain 2.78 %
0.13 lb Golden Naked Oats (8.0 SRM) Grain 2.78 %
0.36 oz Cascade [6.30 %] (60 min) (First Wort HopHops 18.4 IBU
0.12 oz Challenger [6.30 %] (60 min) (First Wort Hops 6.1 IBU
0.06 oz Cascade [6.30 %] (45 min) Hops 2.6 IBU
0.06 oz Cascade [6.30 %] (15 min) Hops 1.3 IBU
0.12 oz Challenger [6.30 %] (5 min) Hops 1.1 IBU
0.50 items Whirlfloc Tablet (Boil 15.0 min) Misc
1 Pkgs SafAle American Ale (Fermentis #US-05) Yeast-Ale


Mash Schedule: Single Infusion, Medium Body, Batch Sparge
Total Grain Weight: 4.50 lb
----------------------------
Single Infusion, Medium Body, Batch Sparge
Step Time Name Description Step Temp
40 min Step Add 5.63 qt of water at 130.2 F 122.0 F
40 min Step Add 5.63 qt of water at 188.5 F 153.0 F

 

[brewmasterpa]

ok so i have yet to understand the exact importance of checking gravity before the boil. arent we fermenting after the boil?? i would imagine it would be to verify conversion, but if your technique/equipment are up to par, why does it matter? cant you do an iodine test anyway? im confused to the importance of why people worry about preboil gravity. please fill me in to the importance somebody, i genuinely do not understand.

 

[carnevoodoo]

ok so i have yet to understand the exact importance of checking gravity before the boil. arent we fermenting after the boil?? i would imagine it would be to verify conversion, but if your technique/equipment are up to par, why does it matter? cant you do an iodine test anyway? im confused to the importance of why people worry about preboil gravity. please fill me in to the importance somebody, i genuinely do not understand.

I check my preboil gravity to make sure I am within the range I expected. If I am higher or lower, I can adjust my hop additions accordingly. Typically, I will have a set expectation on this, but with a refractometer, it only takes 2 drops and 30 seconds to check, and it is good to keep on top of your numbers.

I don't bother with an iodine test, because you can taste your wort to verify conversion. I mean if it tastes like sweet wort and it is sticky, you have conversion. I've never had a batch not convert on me.

 

[cyberbackpacker]

Right... well the wort was sweet and sticky, at 4.25 gallons and 1.030 it comes out to ~76% eff into the boiler. What I am puzzled by is how I only ended up with an OG of 1.042 into the fermenter and only ~65% eff.

That is what puzzles me... reasons why I was so far off my target OG into the fermenter of 1.050 when I quite clearly had good (slightly higher than anticipated- 76% vs 75%) conversion into the boiler.

 

[david_42]

Definitely a puzzle. 4.25 gallons at 30 points (127) does not equal 2.375 gallons at 42 points (100). One or more of your measurements is off.

 

[cyberbackpacker]

EDIT: should have been 2 3/5 gallons into fermenter.

Nevertheless, yeah, it is weird.

My measurements for volume in the BK are constant, and were used for both volume measurements.

OG was measured with both samples at 67F and 68F (statistically insignificant difference).

Temps were measured with same thermometer.

 

[s1080]

ok so i have yet to understand the exact importance of checking gravity before the boil. arent we fermenting after the boil?? i would imagine it would be to verify conversion, but if your technique/equipment are up to par, why does it matter? cant you do an iodine test anyway? im confused to the importance of why people worry about preboil gravity. please fill me in to the importance somebody, i genuinely do not understand.

Its been my understanding that the main reason a pre-boil gravity measurement is taken, and thus so important, is to determine a brewhouse efficiency percentage. This figure can then help the brewer by "grading" the methods and techniques used for mashing/lautering.

 

[SpanishCastleAle]

cyber,
Are you correcting the volume(s) for temp? 4.25 gal at 170 F is not 4.25 gal...it's more like 4.25*.97=4.12 gal. That prob won't account for all of the discrepancy but it would contribute to it.

I measure pre-boil gravity for a couple of reasons.
1) If I happen to come up high or low on that gravity I can correct it by either adding DME or adding water such that my OG is correct. If I add water then I'll have leftover wort (i.e. volume will be high but gravity will be correct)...and I'll just freeze/save that leftover wort for starters or something. This rarely happens but it does happen.

2) I like to know the numbers throughout the process. I like to take good notes about each brew. If you brew a high grav brew with lots of whole hops and then a low grav brew with low amounts of pellet hops...the 'boil efficiency' will differ. In the former case you have way more trub and hops in the kettle...which will be a bigger loss than the low grav brew. IMO, if you brew a lot of different styles and gravities then you need to measure the pre-boil gravity to hit your exact OG and volume.

 

[goatchze]

ok so i have yet to understand the exact importance of checking gravity before the boil. arent we fermenting after the boil?? i would imagine it would be to verify conversion, but if your technique/equipment are up to par, why does it matter? cant you do an iodine test anyway? im confused to the importance of why people worry about preboil gravity. please fill me in to the importance somebody, i genuinely do not understand.

It also helps if you need to cover a mistake (esp. gravity too low).

It's a lot easier to measure before the boil and realize you need to add time to get the gravity up (obviously with less total volume now) than trying to measure during/after the boil.

Plus, it's good to know how you stand as far as conversion. You won't really know that your technique is up to snuff or not without it.

 

[tetrylone]

Temperature difference in checking gravity perhaps??

 

[brewmasterpa]

well ive been checking gravity after the boil and figuring efficiencies from that number, and ive been getting from 75-85%. does that mean my efficiencies are actually 90+%??
thatd be awesome! my beers always turn out awesome and ive brewed many many different styles. they always turn out between that range in efficiency. i never adjust my gravity with dme or water, i just go with it. ive only had one batch that turned out watery, and thats because i was grossly low on wort after the boil (was my first ag and i didnt use nearly enough sparge water) i guess im just a guy that makes good beer but doesnt care too much about the science behind it so ill never be a professional. oh well, i still make good damn beer.

 

[cyberbackpacker]

cyber,
Are you correcting the volume(s) for temp? 4.25 gal at 170 F is not 4.25 gal...it's more like 4.25*.97=4.12 gal. That prob won't account for all of the discrepancy but it would contribute to it.

I measure pre-boil gravity for a couple of reasons.
1) If I happen to come up high or low on that gravity I can correct it by either adding DME or adding water such that my OG is correct. If I add water then I'll have leftover wort (i.e. volume will be high but gravity will be correct)...and I'll just freeze/save that leftover wort for starters or something. This rarely happens but it does happen.

2) I like to know the numbers throughout the process. I like to take good notes about each brew. If you brew a high grav brew with lots of whole hops and then a low grav brew with low amounts of pellet hops...the 'boil efficiency' will differ. In the former case you have way more trub and hops in the kettle...which will be a bigger loss than the low grav brew. IMO, if you brew a lot of different styles and gravities then you need to measure the pre-boil gravity to hit your exact OG and volume.

Spanish... no I did not take the thermal expansion into account, thanks for reminding me. As you mention it explains some, but definitely not all of the "funniness".

Also, your reasoning for measurement falls very much in line with why I do what I do. Another is I agree with some on here who have no problem just brewing and saying "hey it tastes great" and do not care about the science/recording/etc. but I'm the type of guy who loves to drink great beers over and over. So, if I make a great beer, and have all of my notes on it from measurements through to serving, I can replicate it fairly honestly and drink that same great beer over and over.

Back ON TOPIC... any other ideas on my weird numbers?

 

[brewmasterpa]

well you can make the same great beer over and over without having the gravity notations as long as your technique and recipe is the same, thats how i do it. my beers are consistently good.

 

[SpanishCastleAle]

I used my corona mill for the first time on this batch, but compared to a crush I had from Northern Brewer (side to side comparison) I had a nice crush without any shredding of husks.

Hit all my temps, and on sparging I collected 4.25 gallons of 1.030 wort (est OG was 1.042)

After the boil I collected about 2 3/5 gallons of 1.042 wort (est OG was 1.050).

My only other guess is that your Corona mill changed your efficiency and somehow one of your measurements got skewed.

 

[flyangler18]

well you can make the same great beer over and over without having the gravity notations as long as your technique and recipe is the same, thats how i do it. my beers are consistently good.

And that's perfectly acceptable - if you're making a beer that satisfies you with your system and process, have at it! There's room for scrutinizing and obsessing about the details and minutiae in the hobby, as well as just makin' beer.

I guess I fall somewhere in between. A point here or there doesn't get my panties in a bunch, but I like to analyze my process for consistency and repeatability. Understanding the science of brewing, the calculations, the yeast management - all just add levels of enjoyment for me.

 

[brewmasterpa]

oh i agree, but my enjoyment comes from compiling the recipes. i have never pirated another persons recipe, i make up all my own. and it is absolute satisfaction when i throw a party at my house with 30 people, have one cooler full of commercial beers, and i buy the good stuff (new belgium, sam adams, gordon biersch, etc.) and one cooler with my stuff, and by the end of the night, my cooler is empty, and the other hasnt been touched. that says something for the non-scientist.