Brewhouse efficiency - low 50%

[safcraft]

Hi all,

Yesterday was my first attempt to do an all grain batch.
I milled the grain myself using a pasta roller (what a mess this was...)
I mashed in the electric boiler, at 150-160F for 90 min.
- 7.5L water
- 1.1 Kg Pilsner
- 1.9Kg Wheat

After this, as i did not use a grain bag, i transfered the wort and grain to a bucket where i have a stainless steel net/filter , to do the vorlauf and sparge.
I sparged 2 times, first with 7.5L water at 170F, then with 3L water also at 170F.

In the end i got around 13.5L of wort collected, which i transfered back in the boiler , to start my boil.

At the end of boil, after chilling i ended up with only 9L of wort , with 1.052.
I reached my intended FG, but at a cost of low wort volume.
Calculating brewhouse efficiency, it gives me around 50% !!! ouch !

What could be the cause for this low efficiency?
As i did not loose much in the sparge bucket (about 500ml in the bottom of grain bed) i am thinking my grain mill was not right?
I was milling quite fine...had a lot of flower and thought i could have a stuck sparge....but did not.

I will perfect the grain mill rollers , as i milled the wheat quite easliy, but the barley was a pain ! The mill just would not pick it up...very very hard to mill it.

Any pointers i should be focusing on besides the milling ?
Cheers,

 

[McKnuckle]

To put this into gallons (rounded) for the metrically challenged:

You mashed and sparged with a total of 4.75 gal.
You delivered 3.5 gal. of liquor to the boil (loss of 1.25 gal.)
You collected 2.375 gal. of wort to ferment (loss of 1.125 gal.)

The boil loss is very normal. The lautering loss is a bit much.

You used about 6.6 lbs of grain, which would absorb roughly 0.11 gal/lb, or a bit less than 0.75 gal. That leaves another 0.5 gal. of loss not spoken for - well, minus the amount you know was left in the tun, it's about 0.37 gal. remaining to be explained.

This being said, most of us don't use brewhouse efficiency as a standard. We are more concerned with recovery of sugars from the grain, or mash efficiency (a combo of conversion + lautering efficiencies). It looks like you hit about 76% by my rough calculation, which is more than respectable. I'd work on not losing as much liquid throughout your process.

You don't say how much wort you expected to yield at the end. What was that figure?

 

[safcraft]

I expected to yield about 11L....but it seems i was being optimistic as i do not know my math !
How do you came out with 76% mash efficiency ?

I am using some online calculators and am getting 60% for mash efficiency (take in mind my pre-boil gravity was 1.042 for 13.5L....after boil it reached the 1.052 for 9L).

EDIT:
On a side note i just remembered an important fact. I was out of bottled water so used tap water. My tap water is around 7.2 ph ...which is rather high i know....but should only impact on fermentability, not on efficiency, right ?

 

[McKnuckle]

If your mash efficiency calculator includes your lautering efficiency - how much wort you actually recover - then the lower value is probably accurate. Because that was my feedback to you: You are losing too much liquid between the mash tun and the kettle. It not necessarily your pre-boil gravity value, which seems quite reasonable. It's that value combined with the volume of wort recovered from the mash.

 

[safcraft]

Thanks for the pointers.
I will replace the bucket with SS filter next batch, for a proper mash tun made from a 45L cooler, with an SS tubing braid. This will have no false bottoms so more wort will be collected.

Problem is i still think the main problem in my wort volume from mash tun (bucket) was due to water grain absorption.
I practically collected only 1L of wort from the first drain ! It seemed like the 6.6 pounds of grain, sucked up all the 2 gallons of mash water...instead the "theoretically" expected 0.75 gal !
It was only in the sparges that i was able to remove all the wort...

EDIT:
Also, when sparging what should be the water temp ? Is it wrong to let the grain cool down a lot during sparging ?
I ask this because after mashing in the electric boiler...i move the grain + wort to the bucket (or mash tun cooler) thus loosing a lot of heat.

 

[Gavin C]

Crush finer/better and refine your process.

Your asumptions about water ph etc are not correct WRT efficiency and fermentability.

This thread might be useful in understanding efficiency better. Best of luck going forward.

Efficiency Calculations

 

[McKnuckle]

If you mashed with 7.5L of water and used 3 kg of grains, I'd expect you to lose between 1.68 and 3L, yielding between 5.82 and 4.5L into the kettle for your first runnings. This assumes no loss in the tun. I'm using an absorption rate of between 0.065 gal/lb and 0.12 gal/lb (sorry, back to English units).

If you sparge, just add the sparge water volume to the first runnings yield, since there's no additional loss.

Sparge is supposed to be 168-172F, but I've heard of cool sparging also, which is said to not negatively affect anything. I don't think that part is important in your situation.