Hitting really low gravities!

[checkers]

Hey guys,
So just put down my 3rd all grain brew in my electric 50l converted keg.
I'm hitting ridiculously low gravities.
Like I mean I have setup my brew smith profile as 65% efficiency and I'm hitting like 50%

Here's what I did today

4kg BB ale malt
1kg BB wheat malt
.3kg crystal malt

Mashed in at 71c
After stiring and getting all the grain roughed in nicely it was 65c
Thinking it hadn't mixed properly I continued to stir and it dropped to 61c
I cranked up heat and within 25mins of adding grains I had it up to 67c and it sat perfectly for the remaining half hour..

All this said and done The gravity reading was taken at 20c just before I pitched the yeast and I got a reading of 1.040

Brewsmith predicted 1.050 at 65% efficiency.... So where did I go wrong?

 

[Crusty]

Are you cracking your own grain?
How much water did you mash in with?
What volume are you getting into your fermenter?
How long are you mashing for?
I hope you stirred the mash whilst heating it up to 67deg.

 

[antiphile]

A few things come to mind.

Firstly, a grain bill of 38% specialty malt is, IMHO, waaaay too high.

Is this a BIAB? Have you considered sparging the grains (whether BIAB or not)?

It would help heaps if you could give a lot more detail of your method.

 

[checkers]

The LHBS here in Perth cracks it for me,
Mashed in with 30L,
Aimed for 20L but squeezed in 22L
Mashed for 60min then ramped up to 72c for 10 mins
Yep stirred my ass off.
I scorched my second brew and completely ruined it

 

[Jack of all biers]

Firstly, a grain bill of 38% specialty malt is, IMHO, waaaay too high.

Since when is Wheat malt a specialty malt? 300gm of crystal is fine in a 5Kg bill. Antiphile is right though a few more details would help.

 

[Jack of all biers]

Just pipped me to the post with your reply.

I recently had a few efficiency issues and it was a combo of problems, the worst of which was the thermometer was giving a false reading which sent my mash schedule out. You may need to check a few things, such as mixture of wort when you are testing it, hydrometer and thermoter accuracies, before you look at the crush of your grain or mash pH etc... As I found in my in-efficiencies, user error is mostly to blame. See thread http://aussiehomebrewer.com/topic/86724-spargeefficiency-issues/ for my lessons learnt.

 

[manticle]

A few things come to mind.

Firstly, a grain bill of 38% specialty malt is, IMHO, waaaay too high.

Is this a BIAB? Have you considered sparging the grains (whether BIAB or not)?

It would help heaps if you could give a lot more detail of your method.

Did you miss the .? They are small, I agree but 300g in 5kg of base is not 38%.

 

[antiphile]

Oops. Sorry Jack, after you posted I noticed the decimal point before the "3". Many apologies to all.

Edit added: Too slow to correct my stuff up. :blush:

 

[Pokey]

I'd not stir it so much, sprinkle the grain in and you should avoid dough balls, give it a good stir. Leave for 90 minutes then do the mash out step. A longer mash shouldn't affect flavour but may help efficiency.

Also try not to change too many things all at once, that way you can identify where the improvements are.

 

[checkers]

Ok, using stc 1000 to control/read the temperature, yep it's biab.. Sorry for that.
Using 50l converted keggle, 3pc ball valve sits at 8L in the vessel
Keg king heating element sits at 10L
Instead of bag I'm using a 19L big w pot with slits in the bottom to put my grain in..
I'll post some pics of my setup now

 

[checkers]

 

[checkers]

I'd not stir it so much, sprinkle the grain in and you should avoid dough balls, give it a good stir. Leave for 90 minutes then do the mash out step. A longer mash shouldn't affect flavour but may help efficiency.

Also try not to change too many things all at once, that way you can identify where the improvements are.

Cheers bud I'll give that a try next time. That was my aim but when temp was low I tried to fix it.
Next time I guess I'll try strike water at 73c?

 

[checkers]

Just pipped me to the post with your reply.

I recently had a few efficiency issues and it was a combo of problems, the worst of which was the thermometer was giving a false reading which sent my mash schedule out. You may need to check a few things, such as mixture of wort when you are testing it, hydrometer and thermoter accuracies, before you look at the crush of your grain or mash pH etc... As I found in my in-efficiencies, user error is mostly to blame. See thread http://aussiehomebrewer.com/topic/86724-spargeefficiency-issues/ for my lessons learnt.

Cheers bud.
I'll look into it and start with the process of elimination..

 

[Yob]

Not efficiency related..but.. How do you lift that pot out?

 

[Topher]

Do you do any recirc or sparge? Recirc helps my BIAB efficiency heaps.

 

[QldKev]

Do you do any recirc or sparge? Recirc helps my BIAB efficiency heaps.

This would be my guess. I think with the BigW pot insert either recirc or a decent sized sparge is needed.

 

[Droopy Brew]

I reckon that pot might be the issue. I dont think the wort is mixing through the grains enough as there are no holes/slots in the side. I reckon if you try using a bag or modify the BigW pot to allow more wort/grain contact then you will go a long way to solving your problem. I would buy a bag and try that first though and see if it is the issue. If it is then go to work modding the pot.

 

[contrarian]

Just punched some of your numbers into the BIABacus and it doesn't agree with beersmith. In fact to get 1.050 from your grain bill I had to adjust the efficiency up to about 75%.

I guess the first question is what efficiency are we talking about. Mash efficiency or brew house efficiency?

If I read your posts correctly you are leaving 8L or about that in the kettle below the tap? If so that will drop brew house efficiency. Although knowing your mash efficiency will be of the most benefit to it is worth taking a preboil gravity measurement.

Another thing is that you got 22L at 1.040 when you expected 20L at 1.050. There is a direct relationship between volume and gravity. V1xG1=V2xG2

So 22x40=20xG2, G2=44.

In this case the extra volume accounts for 4 gravity points.

So there's a few options to hit your targets. If you are not recirculating it might be worth trying a brew with a cheap bag, you will get more transfer between the grain and water than with the pot.

Do a 90 minute mash, the extra time does make a difference.

Do a mash out, raise temp to 75C and hold for 10-15 minutes before pulling the grain.

Measure everything so you know gravity and volume at different points in the process. This will help you understand what is going on in terms of losses to grain absorption, boil off and trub and help you tune in your system.

At the end of the day you still made beer so don't worry too much about he numbers!!

This post was written over a couple of hours with kids going nuts so apologies I it isn't that coherent!

 

[MHB]

Just a couple of points that might help
72oC isn't a mash-out, a mash-out is designed to end enzyme activity and improve the wort fluidity, try 78oC
Calculate your strike water temperature, don't guess and make sure you have a reliable thermometer.

You need to be getting the sugars out of the grain and into solution, you have a tap there so just draw off a couple of litres of wort and return it to the top of the grain bed, doing that regularly throughout the mash will stop the extract just building up in the grain pot and blocking more extract from coming into solution.
Your mash in L:G is over 5:1, but in the grain pot your 5.3Kg of grain is in at most 12L of water, effectively a L:G of 2:1 or so, that will cause all sorts of problems - I'm guessing a small pump would be a really good idea.
Mark

 

[Yob]

I reckon that pot might be the issue. I dont think the wort is mixing through the grains enough as there are no holes/slots in the side. I reckon if you try using a bag or modify the BigW pot to allow more wort/grain contact then you will go a long way to solving your problem. I would buy a bag and try that first though and see if it is the issue. If it is then go to work modding the pot.

You don't want holes in the side but you do want a sparge