Horrendous Efficiency

[Matt12398]

I know there's quite a few old efficiency threads but why not have another one.

Had a brew day yesterday which went very well in most respects. Mash pH bang on, pre-boil gravity bang on, starting gravity bang on. Those are all great things but there were a few things which point to something being wrong.

Despite the gravities being exactly as hoped, the final volume was significantly lower than expected. This could be due to excessive boil off but if my starting gravity is what I hoped but with a lower volume it suggests a serious efficiency problem. My dead space losses are quite small so I don't think they are a major contribution.

I have a slotted copper manifold but I batch sparge and even if I fly sparged I made sure the manifold was suitable for both sparging methods. The calculated efficiency is probably less than 60%. I've always struggled to get above 70% but I don't understand why when people are saying they are getting 80%+.

Any suggestions or thoughts welcome.

[Normski]

Hi Matt

So what was the recipe and exact grain bill.
What were you expcting from them, and what did you get?

[Matt12398]

Hi Norm. This was the grain bill. The slightly random amounts of crystal malts are because of not quite enough light crystal so I used some dark.


Ingredients:
------------
Amt Name Type # %/IBU
4.60 kg Maris Otter (Crisp) (7.9 EBC) Grain 1 69.3 %
0.90 kg Brown Malt (Crisp) (128.1 EBC) Grain 2 13.6 %
0.81 kg Caramel/Crystal Malt - 30L (59.1 EBC) Grain 3 12.3 %
0.17 kg Crystal Dark - 77L (Crisp) (147.8 EBC) Grain 4 2.6 %
0.15 kg Black (Crisp) (1339.6 EBC) Grain 5 2.3 %

I was conservative and based the recipe on 68% efficiency in Beersmith. The recipe is based on 25 litres final volume at 1.056 but in reality it was more like 21 litres at 1.056.

[scuppeteer]

Quite possibly the malt, we use Crisp and have noticed a definite drop in extraction over the past few weeks. I only have a small copper at home and generally brew to a higher gravity and then liquor back if I want a particular final volume, otherwise it is what it is and end up with 18-20l when based on a 23l length.

[Matt12398]

I might try with a different malster next time and see if it makes a difference.

[Subsonic]

70% is quite ok - I get this everyday. Recently I've started malting my own and my efficiency has dropped through the floor. I blame the maltster..... Sub

[Matt12398]

I have been reading your thread with interest. I'd love 70% but I think I'm getting less than that.

[Subsonic]

What is your mash tun? Sub Oops double posted. I never had much luck with slotted manifolds, went to stainless steel braided hose then proper folding SS false bottoms. My efficiency rocketed.

[Matt12398]

It's an igloo cool box. I'm going to see how my brothers Thermopot with perforated stainless false bottom performs and that that might highlight where the problem is.

[Subsonic]

The other thing to look at is your hop schedule. They can absorb a lot of wort.
Those slotted manifolds tend to lay flat so sometimes leave a lot of deadspace that you need to factor in. With a keg it has a dished bottom and what with a false bottom you can drain off pretty much everything. I used to use a coolbox and slotted manifold too. But really your brew is not that bad really, we all have off days so if its a one off now worries. If its a constant just up the grain bill and factor it in, grain is cheap - at least for you guys in the UK! Sub

[subfaction]

I've found a steady but significant falloff in mash efficiency as the grain ages, it takes me around a year to nail a 25kg crushed MO sack. Could that account for it?

[Padalac]

Ok so, you only have %70 base malt - your enxymes are all in the base malt so with less base, you're going to struggle to convert all the starches no? Maybe you need to mash for longer. I have recently started brewing all grain and what got me up from my initial efficiency of 60% in my first few batches up to over 80% in my most recent batch was that I did a 2 step mash and I nailed the ph, but also mashed for longer. Finally I did do a mash out by raising the temperature to 77 degrees and sparged with hotter water (85 degrees). I also switched from continuous sparge to batch sparge. Between these factors i made big efficiency gains.

by the way, if you are interested in trying the two step mash ... the principal is to dough in for a target temp of 40 degrees.. You rest at 40 for 30 mins, then raise up to 60. Hold 60 for 30 mins and raise up to 70. Then you hold 70 for a further 30 mins. Then you mash out to 76.7. This can give you better efficiency, however many people get good efficiency without it, by using a single temp I guess - it also requires being able to heat your mash. HOWEVER in your case with that grain bill... only 70% base malt I really think a step mash would help you.

[techtone]

It's an igloo cool box. I'm going to see how my brothers Thermopot with perforated stainless false bottom performs and that that might highlight where the problem is.

How much liquid are you pouring away during clean-up? You did say your dead space loses are small. Just that, and I know it is frowned upon, but I usually tip both the mash tun and my boiler to make sure I get to the desired volume. (23 litres in my case) Must get at least an extra litre out. As long as you don't go crazy and "disturbing the bed" etc. It all comes out clear and never had a problem doing it. Sometimes, I'll tip the mash tun from the start, so it is already in position before the mash, if I have sufficient volume.

[Matt12398]

@Subsonic - I think Beersmith adjusts for hop losses so should tie all the figures up together.

@subfaction - It's about 10 months old now so could be a part of the problem.

@Padalac - I think with the crystal and black there's not a lot of conversion to do. Even so I would have thought the pale malt would have enough diastatic power to convert whatever is left. I'm not sure.

@techtone - You're probably looking at around 1 litre deadspaces in total. Not very much at all.

[Normski]

Hi Matt

With your grain bill.
25l @ 1056 I make that 73%.
If you got 21l @1056 I make that 61%.
That's not so bad. And if your grain is a bit old.
Is it posible that your grain had settled and needed to be mixed up in the sack.
This can make a big difference.
If im in any doubt over the grain quality, i'd just stick an extra 1Kg in the mash.
Norm