3rd AG brew - Efficiency gain of 25 points

[Coxy]

There are a number of topics on here relating to efficiency and new brewers struggling with getting enough fermentables out of their mash, but I would like to outline my experience in working through the problems. I am not new to brewing in general, but am fairly new to AG brewing, having done only 3 partial mashes and now 3 all grain. The first two partial mashes were BIAB for the mashing part, with not horrible, but not good either, efficiency of around 60-65%. I then invested in a false bottom and a ball valve setup on my 19L cylindrical cooler (making it an MLT) with the intention of having immediate efficiency improvements over my BIAB attempts.

Much to my dismay, my efficiency for the 1 PM and first 2 AG brews was dismal, at around 50%! I believe there were a large number of issues causing my low efficiency and have since been corrected. I think many new brewers probably make exactly the same mistakes as I have, so I would like to document them on here and help everyone out a bit.

I don't think I was losing too much in the mash itself; My strike temperature has always been calculated correctly, and I mash for 60 minutes at around 65C, losing only 0.5-1 degree during the entire 60 minutes. I have done iodine tests on the last few which show no reaction to unconverted starches, also leading me to believe that there has never been a problem here.

That leaves sparging. For all previous sparges before today, I have used a batch sparging technique (today I did fly). There are a number of things that I believe that I did wrong using this technique.

Firstly, and this cannot be fixed now, my ball valve was installed about 3cm too high, meaning that the wort has to actually siphon out at the end rather than just drain out. This means that if I lose the siphon while running the batch sparge, which is very possible if the speed of the runnings is not high and air is in the hose, I leave about 1L of wort at the bottom of the MLT. There is no real way to know whether I have lost the siphon as I can't see the bottom of the tun for the grain. This is one of the main reasons I have moved to fly sparging, as the height of the valve is simply not an issue, as the water is always siting about 3cm above the grain bed so it never needs to siphon.

Secondly, everywhere I had read stated that my sparge water should be 77 degrees. This is very, very incorrect for a batch sparge, and even for a fly sparge. It is the grain bed that should be at 77 degrees after adding the sparge water and stirring it through. As I took off the first runnings, my grain bed was dropping about 10 degrees! I'm guessing this very fast loss of heat is due to the cold air being pulled through the grainbed as the water leaves through the bottom. This means that I was adding 77 degree water to a 55 degree grainbed, which was only raising the temperature back to somwhere around 70 degrees. I was running two batches after the first runnings, so the second batch was only a bit higher, at about 72 degrees. At no point was my grain bed getting up to the optimal 77-80 degree range.

Thirdly, the grind of the grain was probably a bit thick. I asked them to grind it slightly finer than they usually do and they were more than happy to do so.

Today's fly sparge - things that I managed to do well (I think):
Mashout: I did a decoction of sorts to perform a mashout. I drew off about 25% of the wort, brought it to the point of boiling (but did not boil for any length of time like a normal decoction) and then added it back into the MLT and gave it a stir. This raised the mash to 74 degrees - not quite the target of 77 but pretty close. My understanding is that performing a mashout can significantly increase efficiency, especially in a fly sparge, as it allows the malt to infuse into the water much better and the water 'rinses' the grains much better once the mash is at this temperature.

I do not have a 3 tier setup (no HLT with a ball valve to run into the MLT), so I was literally scooping water (at about 90 degrees) with a pyrex jug and onto a plastic lid which was sitting at the top of the mash (see image). John Palmer mentions this technique in the lautering section of How to Brew. Note that the water temperature was this high as it was losing quite a lot simply by spreading over the lid - at no point did the grain/wort get above 79 degrees. The lauter was running very slowly from the MLT into the kettle, so in total it took about 90 minutes.

Efficiency of today's process: 75%. That's 25 points higher than the 50% or so I was getting in the last few.

If anyone has any comments about what else may have been causing me problems to begin with or what I could do even better next time, or any questions about my process, please let me know.

Cheers,

Coxy

 

[Trevandjo]

Hi Coxy

I've had similar problems myself and it seems our setups are almost identical.

When you're fly sparging do you stir any of the grain bed? Do you just slowly pour the water in or splash it off something - I use a spoon thing with holes in it but I'm not sure if I'm actually achieving much with it.

Cheers,

Trev

 

[menoetes]

Hi Coxy,

It's a good post sir, thanks for sharing your notes. I've only done one AG so far and guestimate my efficiency was around 60% at best. I tried a decoction of sorts to get up mash temp up again too and had all kinds of trouble lautering for the first time. Compacting the grain bed etc.

I'm going to be trying again in two weeks and will take your point on upping the the sparge water temp and using the lid (I use a course sieve) to see if I can improve my own efficiency.

 

[Ducatiboy stu]

Use boiling water to batch sparge. this will get your grain bed temp up. dont be scared as it wont increase it as much as you think. even by third runnings your grain bed is only going to be in the low 80's. the hot water also helps disolve and rinse out more sugars

Before you do your first runnings add 1.5-2 ltrs of boiling water to the mash and give it a stir. this will help loosen up the grain bed.

Your technique with the container on the grain beed is a good one as it helps stop chanelling. I use a peice of foil or a saucer.

Can you tilt your mash tun ? Try putting somthing under the opposite end to your tap

 

[The Judge]

My efficiency improved from 56% for my first AG to a fairly consistent 75-80% with batch sparging. All the comments about temperature are correct, but also time and persistence.

My routine now is take the first runnings off to the kettle until the grain bed is visibly bereft of wort and the suction on the pump is starting to drop (not the best straetgy for the pump perhaps, but it's not much suction throttle). Then batch in around 6 L of water above 85C. I find it hard to get above 85C as my HLT takes a while to get up there between mashing and the time I want to sparge. I stir the bejesus out of the mash then recirculate this batch for about 10-12 minutes until the wort is running clear again, then take the second runnings.
I repeat the process until I'm at target boil volume.

The key for me there is HOT sparge water, stir and recirculate, allow grain bed to settle and wort to clear, run off wort, repeat until target boil volume.

 

[Ducatiboy stu]

The key for me there is HOT sparge water, stir and recirculate, allow grain bed to settle and wort to clear, run off wort, repeat until target boil volume.

+110%

 

[storeboughtcheeseburgers]

I generally step up the temp.. mash out with boiling water, get it up to say 72, stir and rest for 10-15, recirculate runnings, then put in say 80 degreeish water and do batch sparges with about 10-15 minute rests for the risidual water. I do 44 litre batches, so normally I do one batch at around 80 and then another (or however I need in my 44 litre esky) at a higher temp, closer to 90 - rest each batch for about 10-15, recirculate and drain. The whole process probably takes about 1hr - 1hr 30. Not something I really rush.

Mostly I get about the 75% mark but am not concerned so much with efficiency - its just a number, so long as you reach your fg (which I'm usually a few points ahead on) its all good to me.

 

[jonnir]

How much do you guys recirc to get a clear wort on your runnings? My first one I just went until no grains were coming through but the wort wasn't very clear.

 

[Ducatiboy stu]

until it is just cloudy. normally I use a 2ltr jug to collect and recirc, and do this about 5-6 times.

 

[The Judge]

How much do you guys recirc to get a clear wort on your runnings? My first one I just went until no grains were coming through but the wort wasn't very clear.

It never runs perfectly clear, per se. 10-15 mins on re-circ should get it to a consistent opaqueness that resembles a clean enough wort.
It's not so much about transfering clear wort as it is about transferring high sugar content wort.

 

[Coxy]

When you're fly sparging do you stir any of the grain bed? Do you just slowly pour the water in or splash it off something - I use a spoon thing with holes in it but I'm not sure if I'm actually achieving much with it.

I didn't stir at all for the first 45 minutes or so - I then became a bit concerned with channelling, so I very, very gently stirred the top 50% of the grainbed so that any channels that existed would have to start again. I'm not sure if this is the right thing to do or not or if it had any effect. I pour the water on top of a plastic lid (see OP image) to splash it about to avoid channels forming

Can you tilt your mash tun ? Try putting somthing under the opposite end to your tap

Tilting the MLT would have no effect, as the pickup is right in the centre of the false bottom; this also can't be changed. I think for me it's fly sparging from now on.

How much do you guys recirc to get a clear wort on your runnings? My first one I just went until no grains were coming through but the wort wasn't very clear.

I take about 2L and it doesn't go crystal clear, but yeah, there are no solids coming through

Mostly I get about the 75% mark but am not concerned so much with efficiency - its just a number, so long as you reach your fg (which I'm usually a few points ahead on) its all good to me.

For those of us limited by the size of the mash tun (mine is 19L), efficiency is very important if you want to make a standard size batch of anything bigger than 1.05 SG, as you can't let the grain/water ratio drop below 2L/kg (apparently - not that I've tried).

Thanks for the encouragement folks.

 

[mofox1]

Sound like you're doing all the right things... My first AG, post here, was successful (and tasty) but my efficiency was only 59%. My second was 90%.

I put it all down to the sparge (maybe crush). My first attempt only had one sparge with 70° water, which I drained out after only a couple of minutes. My process the second time was almost pretty much the same as Putrino's.

The first, second, third, etc runnings were drained completely before adding HOT (+80°) sparge water. After adding just enough to cover and loosen up the grain bed, I gave it a good stir, then left it alone and had a beer (this is a very important step and your brew will be ruined without it). It probably also helped I left it alone for 20mins. Give it time to allow the sugars to leech out of the grain.

Even with losing more than half a litre of the second runnings to the floor gods, I ended up with an 31% increase in efficiency (and a OG of 1.054 instead of 1.045 in a 21L batch). And as I mashed low, I'm probably going to end up with a hell of a lot stronger beer than originally anticpated (also okay with that).

Basically, a few smaller hot sparges, with a 15 - 20 min rest, are more effective than a single larger one. Obvious in retrospect... and sounds like you've already worked that out.

The other variable was grain crush - by the time I did my second AG, I had received my mill. My crush was a bit finer than what I got from my lhbs. Did it effect my efficiency? Highly likely. Was it the reason for the much higher efficiency? Probably not.

But the end result in both cases? Beer. :chug:

Mick

 

[storeboughtcheeseburgers]

I generally only recirculate twice or maybe three times.. find with the cisterns it strains pretty much all the crud out and by the time I'm doing my initial runnings it is pretty clear. I find it depends on the grain though, I've done beers that have been a bit more trubby.