50% Efficiency

[stuchambers]

Hey guys,

I have just pitched yeast on my 3rd all grain BIAB and for the third time I have only achieved approx. 50% efficiency into the kettle.
I have varied my crush from almost flour to much more chunky for no noticeable increase. I have varied the water ratios, still no increase.
The grain has been from 3 different batches so it cant be that either.
I know there are so many areas where I could be doing things wrong it is just frustrating I would be happy with 70% but at the moment this seem to only be a dream.

To achieve a 18L pre-boil volume I mash in with 10 litres at 74* to this I add 3.5kg of grain temp settles at 64* mash for 1 hour. Temp after rest varies from 55-63*
After 1 hour rest I add 10 litres of near boiling water for mash out raises temp to approx. 78*. rest for 5 min.
Drain into kettle begin to add heat. Burn the Sh!t out of my hands as I squeeze the bag add this to the boil.
Hop additions as per recipe.

From this brief description of my process can anyone see what I am clearly doing wrong to get such low conversion.

Cheers Stu

 

[bum]

Have they all been particularly high OG brews? My efficiency drops significantly when I brew heavy. [EDIT: thanks to Drew's quote below I saw that I missed that you are brewing high grav. This is probably at least part of your issue, IMO.]

Regardless, as long as your efficiency is constant you can simply adjust your recipes to suit - it'll only be a couple bucks difference.

 

[amiddler]

To achieve a 18L pre-boil volume I mash in with 10 litres at 74* to this I add 3.5kg of grain temp settles at 64* mash for 1 hour. Temp after rest varies from 55-63*

Once the temp drops below ~62'C the enzymes slow down or stop converting altogether. I would try a warmer temp to start with or insulate the crap out of your mash tun. Also a finner grind for BIAB is good so go back to that.

What software are you using for the calcs? What was the target volume and OG into your fermenter for your last brew Vs actual volume and OG into the fermenter? Efficiency IMO should be looked at in the fermenter or final product. Do not forget the SG into your boiler will be lower to account for evaporation from the boil.

Drew

 

[mxd]

As Drew said need some more info, are you only tying to get 15 ltrs into fermenter ?

You should try to get better insulation/temp control around you mash.

 

[seemax]

As low as 55C after a 1hour mash?? Definitely work on the insulation - camping mats, foam, doona, whatever it takes.

What sort of grain are you using?

I only ever manage 60% efficiency preboil with no sparge BIAB... but honestly at $30 for a sack of JW it bothers me none.

 

[gjhansford]

No one's mentioned pH yet?

I found that when I took care of the mash pH efficiency improved.

ghhb

 

[felten]

Are you mashing in your kettle? how big is the kettle?

BIAB relies on using the full volume of strike & sparge water combined (~30-35L). It sounds like you are limited by pot size in which case you need to add in a sparge step to reach your preboil volume, IE. 20L biab or maxibiab, there are threads on this forum that outline a method for it.

 

[BOG]

Your mash temp is too low.
If you are loosing that much over the mash period then start 2 degrees higher than your target temp.

BOG

 

[dave_h]

Im very new to BIAB (only done three like yourself) but I noticed last time that when I did two sparges there was a lot of sugars still available, this raised my efficiency from around 55 to 65/70. I ended up with two pots (19l + 10l) but after a 90min boil I had about 22l.

 

[stuchambers]

Hi all.
Thanks for your replies there are some interesting things to think about there but the most interesting to me is the mention pH.
I know the mash still should be successful at these lower temperatures as I have read extensively that the conversion occurs almost completely in the first 30 mins of the mash. Even if this is not the case it the amylase enzyme is still active at 38* therefore would still be converting. I also think that sparging could be an issue however last brew I did a single sparge with 10L of 90*ish water and still achieved low efficiency.
Could someone please give me some more information on how pH effects mash or point me to a reading please.

Cheers Stu

 

[MHB]

Unless the water chemistry in Launcesten (?) is so screwed up that it sets like cement, Its going to be the temperature (it usually is), if you havent got a good thermometer youre pushing shit up hill.

People rabbit on about pH, Crush water chemistry or what have you. Remember the test youre doing 50% as well as is conducted in distilled water, with no pH or salt additions. Yes these things are important but get the most basic part right first, then worry about the refinements.

$10-15 for a good glass laboratory thermometer, if its electronic or mechanical dont trust it unless you have calibrated it.

MHB

 

[RdeVjun]

Im very new to BIAB (only done three like yourself) but I noticed last time that when I did two sparges there was a lot of sugars still available, this raised my efficiency from around 55 to 65/70. I ended up with two pots (19l + 10l) but after a 90min boil I had about 22l.

Interesting observation Dave! That echoes the reasoning behind Maxi-BIAB, which is similar to the 20L stovetop method. Lower Liquor:Grist ratio during the mash = more remaining to be sparged, do that and it should be happy days.
Linked both guides earlier today, here is the latter and the former.
FWIW, yesterday's Maxi-BIAB I did was at 82% efficiency into the fermenter, not at all unusual to come in over 80%. Water chemistry (enough calcium) and/ or pH (as ghhb mentions above) are probably limiting factors for the OP, however so is draining the bag sensibly at each step.

 

[Thirsty Boy]

Surely this is, or should be obvious... If you mash at the same liquor to grist ratios that people who use traditional systems mash at... Of course you need to sparge to get any sort of decent efficiency. If you've read even the ost basic description of brewing i dont see how this could not be obvious.

BIAB works without sparging becuase it uses such high amounts of mash water. Those guys who are mashing etc in small pots and cant use the high L:G ratios (maxi BIAB guys etc) - they either sparge or get shitty efficiency and are happy with it. Yu are doing neither... Of course its not going to work very well.

Read some more, or just follow completely, the directions of more experienced brewers. Not trying to be rude, just being realistic. Nick JD, Rde Vjun, Pistol Patch - have all written extensive articles on different ways to do this stuff sucessfully. Pick a method, do what they say - and it will work. Decide you know what you are doing and you can mix and match the methods (which is what you seem to have done).... Then you're probably heading for shitty results (which are what you seem to be getting).

 

[haysie]

Whats the difference between the OP mashing at a low liquor to grist ratio, then adding boiling to bring the temp up or using a high liquor to grist ratio for the mash?

 

[MHB]

Ya sort of what I was thinking (freely admitting I'm not really expert at BIAB) but he's ending up at 5.7:1 (l/g) I would have thought that if he was getting reasonable conversion by the time he mashes out, the extraction would be a hell of a lot better than 50%.

Even with mashing in at 2.85:1 I can't see how he can get that bad a yield, unless the starch simply isn't getting converted.

M

 

[Thirsty Boy]

The way the starches gelatnise in the the high liquid ratio environment and thus the speed of conversion. And in the smaller pot, I think he's still not bringing it up to the very high L:G ratios in BIAB. Depends on the batch size i guess. I have no doubt that the temperatures are playing a role too. Probably.

Whats the main difference? Do it as suggested in the various guides and it works well, do it his way and it apparently doesn't.

 

[dr K]

To follow on from MHB's and Thirsty Boy (as always) well thought comments.
Just say I posted that I was worried about my efficiency in a traditional system.
That I mashed 3.5kg of grain at 2.85:1 (ish) L:G, that is 10 litres.
I then used 10 litres of sparge water, all fine so far, a sort of low sparge cf no sparge
For a pre-boil of 18 litres !!!! how are you going to 18 litres of wort out a total liquor volume of 20 litres
Answers, sparge more or top up with water (as in no-sparge)
But this is BIAB so you squeeze balls out of the grain sack, along with a sack load of tannins and get lots of replys about temperature and pH , when, as Thirsty Boy points out..the answer is bleeding obvious.

K

 

[kelbygreen]

I have been getting about 65% efficiency with my brews in a 20lt pot but I am using 5kg of grain (coz of shit eff) been mashing 3:1 so use 15lts to 5kg and sparge with 6 lts this makes the pot full to the brim. Tomorrow I am planning to do a true mash out and do 2 boils as only have 19lt pot, So mash in at 66c with 15lts of water for 75min then add 10lts of 100c water for mash out of 78c for 15mins. sparge with about 9lts of 81c water.

I know I am adapting both methods in this but I cant see why my efficiency wont improve. I am adding a mash out and I am sparging with more water so hopefully I can increase the efficiency only thing is I will be doing 2x 90 min boils and my boil gravity may be higher then expected so will have to calculate that before I start the boil. the extra mash and sparge water will just be boiled with no hops. damn I wish I had a 80lt pot lol

 

[Tony]

can anyone see what I am clearly doing wrong to get such low conversion.

I cant see why my efficiency wont improve.

I know this has been said before, and i know people BIAB due to space constraints and no im not being a smart arse............. im serious!

Lose the bags and get a false bottom.

 

[JestersDarts]

I know this has been said before, and i know people BIAB due to space constraints and no im not being a smart arse............. im serious!

Lose the bags and get a false bottom.

I disagree - I think it's the lack of sparge that is the problem. The sugars are most likely there, but 'stuck' in the mash. I'd suggest trying to sparge water at mashout temperature to extract more sugars.