[Iliff Ave]

I have brewed a particular batch twice with a few procedural changes that I will note. Batch 1 had an OG of 1.078 and a FG of 1.010 (87% attenuation, 8.9% ABV). Batch 2 had an OG of 1.078 and a FG of 1.020 (74% attenuation, 7.7% ABV).

This is basically a baltic porter with slight procedural changes between the 2 batches. I wanted to decrease the alchohol slightly by raising the FG to make it more appropriate for the style. I decided to decrease the mash length and raise the mash temperature in attempt to achieve this.

Batch 1: 3 hour mash starting at 148F that probably dropped to or below 146F by the end. I was out running errands thus the long mash. There is also about 3% brown sugar to promote some fermentability. I was very surprised to say the least to get 87% attenuation. US05 is the yeast.

Batch 2: 2 hour mash starting at 152F and I assume stayed above 148F. I decreased the amount of sugar as my efficiency was slighty higher to hit my OG of 1.078. No other changes were made.

Batch 1 obviously produced a much more fermentable wort. I am disappointed with Batch 2 and was hoping for a FG between the 2 results I got. Batch 1 is probably the most complex and delicious beer I have ever brewed and I am not sure how Batch 2 can stack up. Batch 2 was bottled yesterday so I won't be able to do a decent side by side for a few weeks. Maybe somehow I will get lucky and it will be better?

Other than a fuller, sweeter beer what differences should I expect? My fear is that although Batch 2 will have less ABV, it will be less drinkable with a syrupy sweetness to it. I am giving these away which is why I am concerned. The good thing is that most people are more apt to drink a 7.7% vs 8.9% ABV beer. A lot of the people who will be receiving one might have been scared away by the ABV level. Has anyone experienced something similar and what were your impressions?

[dmtaylor]

Are you positive that Batch 2 was done fermenting?  How long was it at the final gravity, and at what temperature?

I just can't believe it was done.

My guess is one of three things are going on:

1) Your mash thermometer is not calibrated.

EDIT: 2) Your final gravity readings are wrong.  How did you measure those?

3) You bottled too early and Batch 2 will all be gushers or explosive.

Hope I'm wrong about the last point.

[Iliff Ave]

Are you positive that Batch 2 was done fermenting?  How long was it at the final gravity, and at what temperature?

I just can't believe it was done.

My guess is one of two things are going on:

1) Your mash thermometer is not calibrated.

2) You bottled too early and Batch 2 will all be gushers or explosive.

Hope I'm wrong about the second point.

It is done. It was in the fermenter for 4 weeks with unchanged FG for about 2 weeks. I took my first hydrometer reading at 2 weeks and assumed it wasn't done. I added more yeast, roused the settled yeast, and warmed the beer up to 70F. No change.

The fermentation results I got for batch 2 was actually more of what I was originally expecting when designing this beer.

[dmtaylor]

See my EDIT above, repeated here:

EDIT: 2) Your final gravity readings are wrong.  How did you measure those?

[Iliff Ave]

See my EDIT above, repeated here:

EDIT: 2) Your final gravity readings are wrong.  How did you measure those?

Hydrometer @ 63F. The same hydrometer that was used to measure Batch 1

[dmtaylor]

Okay, is it calibrated?  Does it read 1.000 in plain water at 60-70 F?  Something's just not adding up.  If it's none of these things, then I am as stumped as you are!!!

[Iliff Ave]

Okay, is it calibrated?  Does it read 1.000 in plain water at 60-70 F?

It reads 1.001 @ 60F. I subtract 1 point from all of my readings.

Maybe the wort wasn't aerated enough? Again, I followed my same 'aeration' process as usual so it should be similar to Batch 1 in that way.

[dmtaylor]

Baffling.

Why would fermentation stall?  Did you mess with temperatures during those first two weeks?  Cool it down too early and settle out your yeast before they were done?

Could there have actually been contamination in Batch 1???  I doubt it, but, it could explain a difference.

Could also possibly be an ingredients thing -- maybe you accidentally used lactose instead of corn sugar, or something crazy like that!?

[Iliff Ave]

Baffling.

Why would fermentation stall?  Did you mess with temperatures during those first two weeks?  Cool it down too early and settle out your yeast before they were done?

Could there have actually been contamination in Batch 1???  I doubt it, but, it could explain a difference.

If there is contamination it is the best contamination ever that I hope to reproduce!

As far as fermentation, I kept it in the low 60s until activity began to slow, ramped it up to 70F for a few days, then took my first FG reading after letting it naturally come back down to ambient temp in the mid 60s for a few days. EDIT - Original pitch was 2 packets of US05 into 1.078 wort...plenty

[Iliff Ave]

Regardless of the causes, let's say it's done.

What differences should I expect?

[troybinso]

Why in the world did you change your recipe if batch one was so good?

[Iliff Ave]

Why in the world did you change your recipe if batch one was so good?

I did not change the recipe but I did tweak my mash parameters. Batch 1 had not fully come together in the bottle yet so I couldn't reliably judge it. I was worried it would be too dry at 1.010. I had to get Batch 2 brewed in time to be ready by xmas.

EDIT - batch 2 had slightly less brown sugar by % than batch 1.

[HoosierBrew]

I was worried it would be too dry at 1.010.

Beers that big can have a surprising amount of body and sweetness, even at a low FG. Look at Belgian Trappist beers - Rochefort 10 allegedly attenuates down to near 1.010 FG, pretty astonishing when you drink it.

[dmtaylor]

Okay, back to your original questions... what to expect as far as taste......

I do NOT think 1.020 FG will taste syrupy in such a strong beer.  The alcohol presence will serve to balance out the sugars.  It may, however, need some age to mellow out -- and this goes for both Batches 1 & 2.  Maybe it will taste more appealing after 6-9 months of age, for example.  Before that, it will taste more "hot" in alcohol.

You'll obviously have more body.

I still can't help but assume that somehow or other, you're going to end up with gushers out of this.  Expect high carbonation from Batch 2.  Mark my words.  It might not happen right away, but after a month or two.... yeah.  Be aware of the possibility.

[Iliff Ave]

Okay, back to your original questions... what to expect as far as taste......

I do NOT think 1.020 FG will taste syrupy in such a strong beer.  The alcohol presence will serve to balance out the sugars.  It may, however, need some age to mellow out -- and this goes for both Batches 1 & 2.  Maybe it will taste more appealing after 6-9 months of age, for example.  Before that, it will taste more "hot" in alcohol.

You'll obviously have more body.

I still can't help but assume that somehow or other, you're going to end up with gushers out of this.  Expect high carbonation from Batch 2.  Mark my words.  It might not happen right away, but after a month or two.... yeah.  Be aware of the possibility.

If it isn't done, what would be your advice to get it to finish?