Crown Urn: volume undershot by 6L

[shacked]

After chatting with Barry, I had a crack at his Robust Porter (from the DB - slightly modified recipe below) and ended up with 18L of finished beer in the fermenter when I was aiming for 24L. This was my first go at AG using a 40L crown urn; I've only done stove top BIAB in a pot.

I started with 33L of strike water as per brew mate. Mashed for 80 mins at 65 and 10 mins at 68. SG before boil was slightly (0.003) under expected. At 18L I hit my SG bang on, so I assume my efficiency was way down.

I did a 90 minute boil and had assumed 4L of loss from trub (I measured the trub after transfer and it was about 4L) but only ended up with 18L in the fermenter. It took about an hour to get from mash temp to boil - is this where I lost an extra 6L?

My brew mate settings are for 10% loss per hour of the boil.

Any ideas as to where I've come unstuck on this? Can someone please share their brewmate settings?






Barry's RobPo
Robust Porter

Recipe Specs
----------------
Batch Size (L): 24.0
Total Grain (kg): 6.000
Total Hops (g): 75.00
Original Gravity (OG): 1.054 (°P): 13.3
Final Gravity (FG): 1.014 (°P): 3.6
Alcohol by Volume (ABV): 5.31 %
Colour (SRM): 34.4 (EBC): 67.8
Bitterness (IBU): 45.4 (Average)
Brewhouse Efficiency (%): 70
Boil Time (Minutes): 90

Grain Bill
----------------
4.500 kg Maris Otter Malt (75%)
0.600 kg Chocolate (10%)
0.400 kg Amber Malt (6.67%)
0.300 kg Caraaroma (5%)
0.100 kg Flaked Oats (1.67%)
0.100 kg Melanoidin (1.67%)

Hop Bill
----------------
40.0 g East Kent Golding Pellet (4.7% Alpha) @ 60 Minutes (Boil) (1.7 g/L)
25.0 g Northdown Pellet (8.1% Alpha) @ 60 Minutes (Boil) (1 g/L)
10.0 g East Kent Golding Pellet (4.7% Alpha) @ 5 Minutes (Boil) (0.4 g/L)

Misc Bill
----------------
10.4 g Whirlfloc Tablet @ 15 Minutes (Boil)

Single step Infusion at 65°C for 90 Minutes.
Fermented at 20°C with Safeale S-04

 

[HBHB]

So, you hit gravity but not volume. All is not lost then.

Check your mash pH - did you use mineral additions ?
Check your milling. Is it crushed well.....not too fine....not too coarse....but just like the little bear wanted it.
Check your water. your boil off will be around 2.8L per hr (can vary slightly)

Lots of guys just mash in, wrap well and leave it alone for 60-90 minutes. That's fine and will make beer. But if you want to maintain a slightly higher efficiency, it's worth while to lift and roll the bag 4-5 times during the sacch rest time and to check and adjust the temp each time after rolling. Not much effort for better overall efficiency. Raising to mash out temps while rolling the bag will also help with this. Just my 2 c worth.

Martin

 

[dave81]

Does brew mate give you the "into the fermentor" volume or just a volume?does brewmate account for water loss to grains (something like .8.9l/kg)
did you account for boil off as said, there is 3-4l there.(maybe more for 90min boil)
33l strike water -4l boil off - 6l lost to grain (1l/kg for ease of calcs phew) - 4l to trub in the kettle =19l inti fermentor (need to adjust losses for your equipment)
Just my guess anyway im sure ill be corrected as im still learning

 

[BobtheBrewer]

How do you measure the water that Brewmate tells you that you need for the mash, and how do you measure your trub? 4l of trub sounds a bit much to me, I use 3.3 in my recipe and often have less than that. Also, 6 litres is a very big loss. Is your urn insulated? Makes a definite difference to the boil off rate. Do you squeeze your bag or just let it hang and drip? That can make a fair difference to your absorption rate. You will learn by experience about boil off rates etc, keep good figures. Hope this helps.

Edit: Just ran your recipe through Brewmate using your figures and an absorption rate of 0.30l/kg which is what I use and I squeeze the bag. Total water required was 35.89l, so there is some of your loss.

 

[shacked]

The settings I used were:

Final Volume: 25L
After Cooling: 24L (4%)
Grain Absorption: 0.6 L/KG
% Evaporation Per Hour: 10%
Losses to Trub and Chiller: 0L <--- I think this is where I've messed up.

I should have set the evaporation rate a little higher and added some more water for the trub loses.

When I re-run the recipe with those settings, it gives me a volume that exceeds the size of the urn. I assume I can always reserve some of the strike water in a pot and sparge the bag for some extra volume and do a 60 minute boil?

Other things:

I checked the temp every 15 minutes and gave the mash a bit of a stir and turned the element on (was losing a couple of degrees).
At 75 mins I turned the element on to raise the temp to 68 as per the recipe. It went to 70.
My grain was milled by the LHBS for BIAB.
I just let the bag hang over my bottling bucket and put the run off into the boil.
My urn is not insulated but I did have a towel wrapped around it for both the mash and the boil.
I chilled to 25C with a 12m immersion chiller.

 

[shacked]

So, you hit gravity but not volume. All is not lost then.

Check your mash pH - did you use mineral additions ?
Check your milling. Is it crushed well.....not too fine....not too coarse....but just like the little bear wanted it.
Check your water. your boil off will be around 2.8L per hr (can vary slightly)

Lots of guys just mash in, wrap well and leave it alone for 60-90 minutes. That's fine and will make beer. But if you want to maintain a slightly higher efficiency, it's worth while to lift and roll the bag 4-5 times during the sacch rest time and to check and adjust the temp each time after rolling. Not much effort for better overall efficiency. Raising to mash out temps while rolling the bag will also help with this. Just my 2 c worth.

Martin

Hey Martin,

As an aside, I bought a drop in strainer and ball value off you a couple of weeks ago. Both work a treat (assuming I put the right amount of water in) and were delivered really quickly!!!

 

[Bribie G]

I use Brew Mate as a recipe designer but find that some of its predictions are a bit off. For a Crown Urn for a 23L batch and a 60 min boil, I find that 33L is about perfect, that's up to two litres more than Brewmate tells me.

In your case I'd guess that you really would have been needing up to 36L and a good squeeze at the end. Also I always take that 23L batch to include 3L or so of trub left in the urn, that gives a good volume in fermentor for a keg sized brew.

What I do nowadays is to have marks on the sight tube and getting the correct volume into the fermentor is more of an art, that I've finely tuned over the last few years. You'll get there eventually

 

[BobtheBrewer]

Yes, you do need to figure in your loss to trub. 10% loss to evaporation is a good starting figure. For your total mash volume of 43.72, put in 5 litres less and add after mashout. If you use boiling water you won't take as long to reach your boil. I would still like to know how you measure your water into the urn. I am assuming that you have a concealed element urn, but even if you haven't, the hardware on the bottom will affect your measurement unless you use something like a 1 litre jug which is time consuming.

 

[shacked]

I used a bucket that had 1 Litre marks on the inside. I checked the marks with a kitchen measuring cup and added water 5L at a time. It was a bit slow...

I think I lost about 3.5L to 4L to trub (not allowing for it) and 2L odd to not squeezing the bag enough

 

[indica86]

Following on from Bribie... 36 litres may well overflow when the bag goes in.
With my Crown Urn I use 33 litres everytime. I then "sparge" in a bucket in bucket lauter and drain that into the Crown.
Does not take me an hour to get to boil. Is your element clean?

Keep playing, I am sure you will get something going that works for you.

 

[shacked]

Yeah it was the first time I've used it and it's brand new. I think maybe the lack of insulation and being outside may have impacted the time to bring to boil.

How long does it take you from the end of your mash?

 

[indica86]

Umm, dunno. I can do two in a day. Certainly not an hour to boil.
I insulate for the mash but not the boil.
Keep playing and use the software as a guide.

 

[shacked]

Two in a day would be awesome!!

Today was a bit of a nightmare; probably took over 6 hours from heating the strike water to packing up.

Thinking about having a crack at the 'Lord nelson cascading out of this galaxy pale ale' tomorrow. Got room in my chest freezer for another brew.

 

[indica86]

Easy to do mate. Crack on.

 

[shacked]

Cheers mate!! Will do

 

[Natdene]

Hi shacked, my urn is insulated and it takes just under 40 min to get to boil from the mash

 

[Bribie G]

This is what 33L plus around 5.5 kg of grains looks like. You could easily get in another few litres without overflowing. Remember this is mashing not boiling so it can go just about to the top with no worries, just watch out for boilover when the bag has been hoisted and the wort brought to the boil. Never had a boilover yet.

 

[shacked]

Thanks Bribie G,

When you mash do you leave the element on?

 

[Bribie G]

No I float a circle of bubble wrap on top of mash, wrap in sleeping bag plus metallised foam rubber (Clarks Rubber) sheet and just walk away for an hour or more. Then I pump mash up and down with paint stirrer thing and switch element back on to raise to mashout.

At a "systems war" brewday a few years ago for the QLD Conference, monitored by club members wielding refractometers and large whips , I hit the same efficiency as a couple of 3v systems, one of them recirculating I think (Bradsbrew's) but foggy on that, and a Braumeister.

 

[marksy]

Tip for heating strike water, use hot water from your tap, the same with sparge water.

Fill your urn to just above the tap, then open the tap, when the water stops flowing. Measure how much is left in urn.

It takes a few goes to tune your system, and you`ll find little cheats you can do along the way to make it easier.