Low efficiency?

[Dodes]

Hi,
I'm struggling with the low efficiency for few batches now. I'm using fly sparge.

Today my conversion efficiency was 88.9%, preboil 67%, ending kettle 70%. My last batch was even lower, where ending kettle efficiency was 65%. I was expecting to have about 80% with the fly sparge (at least this is what I hear from other people using fly sparge - and they are getting as fas as 85% kettle efficiency). My mash was 60 C for 45 minutes and 70 C for another 45 minutes. Also done mashout at 77 C. My pH was cca 5.6. I was using pilsener (92%) malt and carapils (8%).
I was searching about bad efficiency but haven't found something to help me out (There most occured topic was bad crush. I'm using corona mill but I have adjusted the setting to get the very soft crush but not the flour). I'm using the electric mash tun. I'm measuring the temperature with digital and also classic thermometer. For the SG I'm using hydrometer and also refractometer. I'm measuring all my samples at the room temperature, that is 20 - 22 C. Fly sparge duration was 1 hour 30 minutes. The one thing I'm worrying about is my fly sparge procedure. When the last 2 - 3 liters was being grabbed from the lautern tun, the wort SG was 1.033. I was expecting a lot less. So maybe my sparge procedure is little bit off.

Other people suggested that I should try malt conditioning. Will try that in the next batch.

What efficiencies do you get? Do you know where could be the problem? Should I mash a little bit longer?

Thank You

Dodes

 

[tochsner]

I was getting about 65%. I worried about it. I tried all the suggestions I could find here. I finally got it to about 70%. Now I just write my recipes with 70% in mind. I hit my numbers every time and the beer tastes great.
I have no idea how people are getting efficiencies in the 80's but I feel so much better since I stopped worrying about it.

 

[Kingbogart]

Efficiency will vary from day to day and recipe to recipe. As a general statement, the higher the gravity the lower the efficiency. When fly sparging I tend to get in the 85%-90% range preboil on normal strength beers, but as the gravity goes up the efficiency drops. I was only at 72% on a 1.093 RIS.

What does your grain bill look like on a batch you've done poorly with?

 

[billl]

Well, you aren't getting full conversion. You should be getting near 100%. The first place to look is your crush. The next place would be to make sure your PH is an an acceptable range.

You also aren't getting a good sparge. Your final running SG means you are leaving a significant amount o sugar behind.

 

[troglodytes]

Your efficiency is slightly better than mine. I use a 10 Gal Igloo cooler MLT and batch sparge. I usually get a conversion efficiency of about 85-88% then things go downhill and I generally end up with about 66-68% brewhouse efficiency. I blame miscalculation of water volume ratios (mash to sparge) and incorrect trub volume assumptions in the brew kettle. I probably leave a bit too much good wort behind in the kettle and figure I can correct it once I have bazooka screen or filter in my kettle. I wouldn't worry about 70% efficiency and I certainly wouldn't call it low, its probably closer to average.

 

[Dodes]

Thanks for all replies,
the receipt gravity was 1.051 but my gravity readings were 1.046 (but I've got a little bit more wort from sparging, about 1.5 L). I don't take the low efficiency as the end of the world you know . But it bothers me. I want to find where the problem is exactly.
The grain bill for the one that has 65% efficiency was: 47.5% Pilsener (treshing floor malt - local), 35% German pilsener, 10% Munich/Bavarian (treshing floor malt - local), 5% Wheat malt, 2.5% Caramunich II.
Yes that conversion efficiency is low. I have the photo of the crush from the previous batch but I couldn't find it now. So maybe I still need to make a more fine crush then. As I wrote in my original post, the pH is 5.6 which should be OK AFAIK. The bad sparge - could be I've used a lot of sparge water? My grist to water ration was 5 L/kg and I've used total of 11 L sparge water to get 20.3 L of wort (preboil).

@troglodytes: Looks like you're having low conversion efficiency too.

Thank you

 

[Kingbogart]

From those numbers it looks like your mash was pretty thin, I usually go with about 2.5L/kg. You have double that. As a result you have much less sparge water, only 11L.

Not having enough sparge water will definitely effect your efficiency. If you were still running off 1.033 when you had collected your full preboil volume, there was plenty of sugar still in the tun and it all went to waste.

 

[Dodes]

Yes my mash was thin. I've read [1] that more thinner mash yields better efficiency. I only started make thin mash when my efficiency has dropped below 70%.
As was mentioned above, the grain crush could be the problem. That's the one thing I try to address. Are there any other suggestions I should make?

Thanks

[1] http://www.braukaiser.com/wiki/inde...ncy_in_single_infusion_mashing#Mash_thickness

 

[RM-MN]

Have you had a stuck sparge yet? If not, tighten your mill and try another batch. If you do get a stuck sparge you got the mill just a little too tight. If you don't have at least a little flour you can't get the higher efficiencies.

 

[troglodytes]

Yes my mash was thin. I've read [1] that more thinner mash yields better efficiency. I only started make thin mash when my efficiency has dropped below 70%.
As was mentioned above, the grain crush could be the problem. That's the one thing I try to address. Are there any other suggestions I should make?

Thanks

[1] http://www.braukaiser.com/wiki/inde...ncy_in_single_infusion_mashing#Mash_thickness

I believe Kai also states that he found that max efficiency from single infusion mashing comes when the sparge volume is equal to the volume of the first runnings (strike volume less grain absorption and dead space). Hence the lower the max efficiency from bigger beers due to less sparge volume available.

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