High Gravity Split Batch - Very Low Efficiency

[luke2080]

My first time trying to do a high gravity beer - Kate the Great clone - did not go so well. Figured since this was such a big beer and only doing a 5G batch, and I have a second burner and BK, to make a batch from the second runnings. Either way, the first batch had an efficiency of 41%. Here was my process - this was clearly operator error, so hopefully someone can help me work this out.

Planned to do a 4.75G batch, the grain bill is below. I did treat the water with some calcium chloride, but after 10 minutes into the mash the ph was a bit low, at 5.18, due to all of the roasted malts. So I put in 1 Tbls of chalk which raised the pH to 5.27. pH measurements at room temp.

Most grain was milled on my mill, same settings I had the prevoius two batches at, where I had 80% efficiency. Some specialty grain was milled at my LHBS, of which I've never had a problem.

15 lbs 0.6 oz Pale Malt (2 Row)
10.8 oz Barley, Flaked
10.8 oz Special B Malt
10.8 oz Wheat Malt, Ger
9.5 oz Carafa III
8.1 oz Aromatic Malt
6.8 oz Caramel/Crystal Malt - 40L
6.8 oz Roasted Barley
3.4 oz Black (Patent) Malt
3.4 oz Caramel/Crystal Malt -120L
3.4 oz Chocolate Malt
1.00 oz Magnum [14.00 %] - Boil 75.0 min
0.70 oz Perle [8.00 %] - Boil 75.0 min
0.70 oz Styrian Goldings [5.40 %] - Boil 75.0 min
0.18 oz Centennial [10.00 %] - Boil 15.0 min
0.43 oz Styrian Goldings [5.40 %] - Boil 0.0 min
0.43 oz Willamette [5.70 %] - Boil 0.0 min
0.30 oz Palisade [7.50 %] - Boil 0.0 min
1.0 pkg Washed - California (White Labs #WLP001)

Mashed for 50 minutes.

Here is where I may have gone wrong....I did a mash out (which I normally do before I fly sparge). I generally add 2 G of hot water to help up the MT temp while I also use a burner (have a stand/RIMS setup). Still probably took 10 minutes to get my MashOut at 168, then kept it there for 10 minutes before I started my 45 minute Fly Sparge. A normal time for me.

My pre-boil gravity reading was 1.048 after collecting 6.75 Gs. It should have been 1081. I knew at that time something was wrong, but it was so wrong I assumed my hydrometer or eyes. (Hydrometer and eyes were both later validated as correct).

Boiled for 75 minutes, the OG for the 4.75 after cooling was 1060.

Did adding water for the Mash Out dilute the the mash for that first runnings?

I would have assumed that, but the second batch using the second runnings has an OG of 1040. So if I averaged that together its 1050, which at 9.5G would be 68%.

The original plan was for 73% efficiency, thinking I would lose some, but do I not mash out when wanting to collect the first runnings for a more concentrated, High OG batch? How are batches like this handed from a fly spargers perspective? Or is this the time you batch sparge?

I had so much yeast ready to go, was a disappointing day.

 

[luke2080]

Bueller?

 

[GilSwillBasementBrews]

Not sure why it was so low. I do know from reading on the forums that high gravity beers always suffer lower efficiencies. However, yours seems lower than most have reported.
It has something to do with having a larger grain bed with the same volume of pre boil you normally have. Being only able to dissolve x amount of sugar into the water. I'm sure someone more knowledgable can elaborate on the reasoning why efficiencies suffer in high gravity beers.

 

[DocScott]

That is an intense recipe...

To your question, your efficiency seems very low to me too. Take this answer with a grain of salt, as I've only done partigyle brewing (like what you attempted to do here) with batch sparging. From what you described and a few calculations, it seems that your anticipated preboil gravity if you did not mash out with the 2 gallons would have been 1.068 (at 4.75gallons) which is still poor conversion. If you boiled this down at 1 gallon/hour boil off, it would leave you with 3.75 gallons at 1.085, around your anticipated. It seems that you have already addressed and excluded the possibility from usual sources, ie. from older grains/poor crush/too short mash. I think this then may be related to a miscalculated recipe and/or volumes. To calculate the appropriate partigyle recipe, look up Mosher's article and tables on this forum. Since this is a large grain bill, and your volumes are lower, your mash ratio may have been a too low, leading to poor wetting/extraction.

I don't have an exact answer for you obviously, however I think I'd suggest looking more into the partigyle recipe development and how to then use it in your brewing software to get anticipated volumes/gravities if you try this again - I think that's where the problem lies. Good luck!

 

[luke2080]

Thanks Doc - I'll read up on the partigyle techniques. We just did it that way on a whim, to capture a second batch from what should have been plenty of fermentables left in the mash. It was the first round of the mash that didn't catch up.

The initial mash itself was 1.3 to 1.4 qts / lbs for a water to grain ratio. I can fit 35 lbs of grain in the MT, which is why I expected not to see much efficiency loss, only having 19 lbs of grain. I'm blaming a too short of a mash time for this bigger recipe, and diluting a little bit with the mash out.

This brew day caused me to pick up a refractometer. This should make a world of difference. When trying to make a beer on the intense side again.