Brewzilla 60L Efficiency Issues / Pushing Capacity?

[Chrispy92]

Hi all,

With a fair few years of brewing experience doing BIAB and overall happy with the quality of the beers I was making i decided to step it up to a 60L Brewzilla all in one electric system. Today I brewed by fourth batch on the system, with the previous comprising three double batches and one single batch. The last two batches I pushed the system to what I presume is its limits (10-12 kg of malt) and my efficiency fell through the floor (~50%).

For context the double batch today was a oat cream IPA as follows:

Mash volume = 48L

Grist:

6kg ale malt (49%)
2.25kg rolled oats (18.5%)
1.7 kg rolled wheat (14%)
0.4 kg honey malt (3.3%)
0.4 kg rice hulls (3.3%)
0.4 kg lactose (3.3%) @ flameout
1kg dextrose (8.2%) @ flameout

OG was 1.054 which is a whopping 49% efficiency.

I have had some trouble getting the wort to filter through the grain bed when the pump is on and typically only get it to just trickle through... any faster and overflows. Acknowledging the above grist is super oat/wheat heavy which no doubt caused a sticky mash but my main issue seems to be that there is some restriction in water movement between liquid in the basket at the remainder of the liquid in the vessel, no matter how much you stir the mash there is very little mixing. This seems to be the only explanation as to why my efficiency would be so low? When I used to BIAB with similar grain sizes I never had this issue (presumably as the entire grainbed was in contact with all of the water in the pot?).

Has anyone else encountered issues like this with the Brewzilla? I feel as though if the basket was perforated on the side walls it would really help water circulation (don't know if there is anything on the market available for this unit). I'm not sure if i should just scale back to make sure I can have the pump running (in which case I feel as though it defeats the purpose of having a system you should be able to push double batches out on).

Any thoughts/suggestions or experience in using this system would be much appreciated!

I feel like I may be better off using my old BIAB bag for big batches to increase the amount of water moving around the grain?

Cheers,

 

[doug293cz]

You say "mash volume" of 48L. Is that your strike volume?

The lack of mixing between wort in the malt pipe, and that between the malt pipe and vessel wall is a known characteristic of malt pipe brewing systems. If you don't do something to homogenize the wort prior to lifting the malt pipe and draining, the wort left in the grain will be the highest SG wort in the system, and your lauter efficiency will take a hit. An easy way to mix up the wort is to lift the pipe, let drain, then lower back into the wort, and repeat 5 or so times. Another way is to return some of the recirculated wort into the gap between the pipe and vessel wall.

To really diagnose mash efficiency problems, the following data is required:

• Grain bill weight
• Grain bill weighted average extract potential
• Strike water volume
• Volume of any additional water added to the mash before run-off
• Sparge water volume
• SG of wort at end of mash (after homogenizing)
• Pre-boil volume and SG
• Post-boil volume and SG

Accuracy of measurements is critical, as the efficiency calculations will be less accurate than your lowest accuracy measurement. It's best if all volume measurements are corrected for thermal expansion the corresponding volume at room temperature.

With the above data your conversion efficiency and lauter efficiency can be separated from the mash efficiency. Doing this separation will tell you if you have a problem with starch conversion, or separating the extract (sugar) from the grain.

Brew on

 

[stealthfixr]

I have a Brewzilla 65L and have done many 5 to 10 gallon batches in it. It seems happiest with 10-14 pounds of malt, and efficiency goes down the more you add. For a typical 5 gallon batch of normal gravity wort, I usually get between 75-80% mash efficiency, and a few times I have saw 83%. Normal is 78%, and I do batch sparge with about 1.5L of 173F water after the malt pipe (grain) has drained for a few minutes.

For a 10-gallon batch, that goes down to ~68-70%. I just created extra Brewfather profiles for each batch size (5, 6, 7.5 and 10gal for me) and tailored the efficiency for each, which seems to work.

That said, 50% seems very low to me.

 

[cactusgarrett]

Don't forget rice hulls. It's an extra step but it's good insurance.

 

[darkhollow]

Same problem. I tend to agree that more grain you use less efficiency you'll get.
Yesterday I brewed 5 gallons batch of russian imperial stout it calls for 9 and a half kilograms (20 lb 12 oz) of grain total.
I've got 66% mash efficiency and 56% brewhouse efficiency.
I noticed that wort was overflowing all the time, and when I lift the cylinder the wort was barely dripping.
I know this is not mill, I've tried 3 different mills with different settings very similar results.
Rice hulls sounds like a good thing to consider when lots of grain is added.
I'd say, the problem is the flow restriction due to the pipe design of the system.