Unexpected Efficency Increase Any Advice?

[smokiethebear88]

I am new to brewing and I did one extract batch and then jumped into BIAB.
On my most recent batch I compiled a recipe for Coffee stout expecting 65% efficiency which is what I got in my previous batch of Blonde Ale, however when I took my gravity reading I ended up with about 70% efficiency!

Please see my brewing recipe procedure below and let me know if you can think of why I had such and increase.

Recipe
10.5 lbs Pale Malt
1.5 lbs Chocolate Malt
0.5 lbs White Wheat Malt
1.0 lb Brown Malt
0.5 lbs Lactose


Mashed Grain + 7.5 gallons of water @ 154 F for 75 Min 152F after 75 min rest

Brought water and grain to 170F after mash let sit for 10 Min then removed bag to drip, only a slight light squeeze nothing different than last batch.


Boiled for 60 Minutes
.75oz Magnum @60 min
0.5 lb lactose @15 min
.75oz Magnum @ 12 min

Ended up with just under 5 gallons of wort added boiled and cooled water to increase volume to 5 gal.

(The procedure for the blonde ale was similar except 60 min mash and over shot 170 bag out temp ended up 175/176)

I don't think and extra 15 min in the mash could give me 5% increase in efficiency

Let me know if you have any ideas?

Thanks,

 

[edroberts]

I've noticed about a 5% difference in conversion efficiency if I squeeze the bag. That said, I've never done a gravity reading pre and post squeeze to know for sure.

 

[smokiethebear88]

Interesting....I did squeeze about the same amount, also both times I put the bag in a bucket and pour in whatever drains off while I bring the wort to a boil

 

[DurtyChemist]

Did you take the sample before you added water? Did you make sure the added water was mixed well enough to change the gravity readings?

Maybe you're still dialing in your process and you can get 70% consistently. I'm currently stuck at 65% and trying to figure out where I can improve.

 

[smokiethebear88]

I poured the wort into the ferm. bucket and topped it off with water to get to the 5 gallons, then drew some wort out for a reading, didn't add much water a liter or so.

I actually think hitting my temps exactly helped some, by stirring the mash in the kettle while measuring temps to ensure I get a reading that better represents the entire mash volume.

Another possibility is the dark malt, the increased acidity in dark malt helps improve the conversion efficiency and this was a very dark beer and also my first all grain dark beer.

 

[danath34]

Couple ideas :

1) are you doing any water treatment? could be this batch was in a better pH range as you mention.

2) are you milling your own grain or buying it milled? I've noticed big differences in crush size from my LHBS and corresponding swings in efficiency.

3) maybe this batch you stirred more?

 

[McKnuckle]

You don't point out if the efficiency you are referencing is PRE boil or POST boil. You're using lactose in the boil. That increases gravity and is not subject to the vagaries of mashing. My bet is that your increase is simply due to the lactose contributing additional post-mash gravity to your wort.

 

[smokiethebear88]

Well I'm comparing post boil to post boil readings, usually I don't take a reading pre boil.

Also maybe it was the lactose? but I guess with the brewing calculator I use I took the lactose into account on the calculator when formulating the recipe and I used the same calculator for the previous batch I was comparing to.

 

[McKnuckle]

My point with fingering the lactose is that it is not subject to "efficiency." It will always yield 100% of its sugar. So if you calculated the recipe with an efficiency of 65% and predicted a certain OG based on that, the portion of sugars from the lactose will contribute at 100%, and mix with the 65% yield from the rest of the fermentables.

Your software would have to be smart enough to recognize lactose as a sugar, omit it from the efficiency calculation, then add it back at 100%. I have no clue if it's doing that, but I tend to doubt it.

 

[McKnuckle]

X

 

[smokiethebear88]

Well I think your point about the rise in OG from the lactose is true, the calculator certainly took into account an increase in OG from the Lactose, however I still don't think it accounts for the increase in efficiency.

Playing around with the calculator:

With 73% efficiency it gave me my actual OG with the lactose 1.072

WIth 73% efficiency without the lactose it gave me an OG of 1.068


I've seen several opinions on how much lactose can increase OG, but could .5 lbs in a 5 gallon batch have caused an increase of much more than 0.004?

I guess worst case scenario the lactose increased OG by 0.006 from 1.066 to 1.072 that still gives me about 70% efficiency which is still 5% higher.

Since I'm new to brewing I don't know if +/- 5% is a big swing

One neat thing about the calculator was that it recognized that the lactose is unfermentable, based on the yeast I used WLP0001 it gives me an expected FG, when I removed the lactose FG went down and expected alcohol content remained the same.