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Attenuation Question

I recently made some changes/upgrades to my brewing equipment and, on my first batch with the new equipment, have noticed a HUGE increase in efficiency. I upgraded from a hydrometer to a refractometer, built a sparge out of PVC to continually sparge in lieu of batch sparging and purchased an oxygenation kit to introduce pure oxygen to my wort. My results and recipe are listed below. Any feedback on the cause, or false readings for that matter, would be appreciated. This is the second time I’ve brewed this beer and both results are listed below. Keep in mind my first batch was using a hydrometer with batch sparging and the second was a refractometer with continuous sparge and pure oxygen.

1st batch recipe:

10lbs American 2 Row
4.5lbs English Marris Otter
.5lbs Briess Caramel 10

60min mash @ 151
Batched @ 170 for 10 min

1oz Summit to first runnnings
2oz Cascade @ 60min
1oz Cascade @ 20min
1oz Summit @ 20min
2lbs Corn Sugar @ 5min
1 Tbsp Yeast nutrient @ 5min
1oz Cascade Steeped for 45min post boil

2 Smack Packs of Wyeast #1272 American Ale 2

4oz Cascade Dry Hopped in Secondary

(Basically NB’s Cascade Mountain recipe only I screwed the bitterring hops up)

1.082 OG
1.012 FG
85.36% Apparent Attenuation
69.14% Actual Attenuation
9.17% ABV

2nd Batch Recipe:

10lbs 2 Row
4.5lbs English Marris Otter
4.5lbs Briess Caramel 10 - I was in a hurry at NB and didn’t realize the mistake until it was too late

60min Mash @ 152
Continuous Sparge @ 170

1oz Summit to first runnings
1oz Summit @ 60min
2oz Cascade @ 20min
2lbs Corn Sugar @ 5min
1 Tbsp Yeast Nutrient @ 5min
1 Tspn Irish Moss @ 5min
2oz Cascade Steeped for 45 min post boil
Wort Oxygenated for 45 sec

2 Smack Packs of Wyeast #1272 American Ale 2
1 Packet of US-05 Dry yeast

1.096 OG - Brix 23 in refractometer
1.005 FG - Brix 11 in refractometer - verified on 3 seperate sites that 1.005 with alcohol adjustment
94.79% Apparent Attenuation
76.78% Actual Attenuation
11.92% ABV

I’m not complaining, just want to understand exactly what I did right so I can do it again!

Looks pretty obvious to me, 15 lbs of grain on the first one and 19 on the second one. That appears to be the difference, not efficiency?

The yeast took the final gravity much lower than the first time. I realize the OG would be much higher with the added 4lbs of grain, I just want to understand what caused the FG to go so low. I didn’t expect the oxygen and fly sparge to make that big of a difference.

[quote=“justink”]I recently made some changes/upgrades to my brewing equipment and, on my first batch with the new equipment, have noticed a HUGE increase in efficiency. I upgraded from a hydrometer to a refractometer, built a sparge out of PVC to continually sparge in lieu of batch sparging and purchased an oxygenation kit to introduce pure oxygen to my wort. My results and recipe are listed below. Any feedback on the cause, or false readings for that matter, would be appreciated. This is the second time I’ve brewed this beer and both results are listed below. Keep in mind my first batch was using a hydrometer with batch sparging and the second was a refractometer with continuous sparge and pure oxygen.

1st batch recipe:

10lbs American 2 Row
4.5lbs English Marris Otter
.5lbs Briess Caramel 10

60min mash @ 151
Batched @ 170 for 10 min

1oz Summit to first runnnings
2oz Cascade @ 60min
1oz Cascade @ 20min
1oz Summit @ 20min
2lbs Corn Sugar @ 5min
1 Tbsp Yeast nutrient @ 5min
1oz Cascade Steeped for 45min post boil

2 Smack Packs of Wyeast #1272 American Ale 2

4oz Cascade Dry Hopped in Secondary

(Basically NB’s Cascade Mountain recipe only I screwed the bitterring hops up)

1.082 OG
1.012 FG
85.36% Apparent Attenuation
69.14% Actual Attenuation
9.17% ABV

2nd Batch Recipe:

10lbs 2 Row
4.5lbs English Marris Otter
4.5lbs Briess Caramel 10 - I was in a hurry at NB and didn’t realize the mistake until it was too late

60min Mash @ 152
Continuous Sparge @ 170

1oz Summit to first runnings
1oz Summit @ 60min
2oz Cascade @ 20min
2lbs Corn Sugar @ 5min
1 Tbsp Yeast Nutrient @ 5min
1 Tspn Irish Moss @ 5min
2oz Cascade Steeped for 45 min post boil
Wort Oxygenated for 45 sec

2 Smack Packs of Wyeast #1272 American Ale 2
1 Packet of US-05 Dry yeast

1.096 OG - Brix 23 in refractometer
1.005 FG - Brix 11 in refractometer - verified on 3 seperate sites that 1.005 with alcohol adjustment
94.79% Apparent Attenuation
76.78% Actual Attenuation
11.92% ABV

I’m not complaining, just want to understand exactly what I did right so I can do it again![/quote]
Did you actually use 2 Smack Packs of Wyeast #1272 American Ale 2 AND 1 Packet of US-05 Dry yeast?

I guess my second question would be, more importantly which beer tasted better?

I would check the FG again with your hydrometer, that FG seem very low. I think that the recfractometer conveters have trouble converting FG on beer with that high of a OG. I may be wrong but checking with your hydometer would confirm your readings.

I did use all that yeast… The beer is carbinating in the keg now, I haven’t tasted it yet.

My hydrometer broke … That’s how I talked the wife into the refractometer

Yeah, me neither, I’m not buying that you really got 95% apparent attenuation. The first one, maybe, but the second batch, no. The only possible explanation I can think of is if your thermometer was way off and you actually mashed at like 147 F or something low like that, to break down all the complex sugars into very very simple ones. But even that is very iffy.

Oh yeah, and one more explanation: contamination. I would think with 3 yeast packs pitched you would have very low odds of contamination, but stranger things have happened.

I’ve never gotten anywhere close to this… I knew something wasn’t right, that’s why I turned to the forum. I’m going to buy a new hydrometer and check.

It seems like the refractometer is only convenient for wort and pre fermentation readings… I feel like its too unreliable for post fermentation readings.

Would everyone agree?

I don’t know. I’ll bet a refractometer is pretty nice. I don’t have one. I should probably knock on wood but I still use the same hydrometer that I bought as a young pup in 1999. I’ve made almost 100 batches always using that same hydrometer. Even dropped it a couple of times, but it never broke. Sure, it reads high by 0.003, but I know that and just subtract it off. Speaking of which…

Make sure your hydrometer and refractometer are properly calibrated. A hydrometer should read exactly 1.000 in cool 60 F water. If it doesn’t, add or subtract to get there, then always add or subtract that same amount from every reading it takes for the rest of its life. I have no idea how to calibrate a refractometer, but I’m sure there are ways.

Also, calibrate often. If you have a hydro that’s prone to paper slipping, readings can change from one batch to the next. I tend to calibrate before every reading, even though the last 20 readings have all been 2 points high.

Check the hyrdo for calibration temps. Some are calibrated at 68*F.

That low finishing gravity isn’t surprising for US-05, especially with O2.

The suggestions about calibrating your hydrometer and refractometer are still valid.

[quote=“justink”]1.096 OG - Brix 23 in refractometer
1.005 FG - Brix 11 in refractometer - verified on 3 seperate sites that 1.005 with alcohol adjustment[/quote]Go to

and download his refractometer correction spreadsheet - using his calcs, an OG of 23 with an FG of 11 equals 1.015, not 1.005. 1.015 is much more reasonable.

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