Persistently low efficiency! even with fly sparging

[jgers]

For the several years of all grain brewing I have consistently achieved efficiencies between 65-70% -- despite reading on this forum about people getting 75-80% on what seems like similar systems. I dont know if my expectations are just out of whack or if I am doing something wrong. I even did my first at-home fly sparge this weekend expecting better results and wound up with a pathetic 66%. I feel like i am just got getting the full potential flavor and its hard to get the right OGs. Please help!

Here is the system I am using:
10g picnic cooler mash/lautering tun with shallow false bottom
10g kettle draining sparge water on top of the mash (new)
final mash rest usually 155ish but often topping off the cooler to mash out in the 160s
sparge water ~190 (on hot side to my knowledge) but knowing it will balance out with the cooler mash tun to put me closer to 170.
On this latest batch i tried to be extremely patient with the flow rate - normally I just open the mash tun valve all the way. This time I opened about halfway to follow the conventional wisdom of slower flow.

Thoughts? Still too impatient with flow rate? Is the problem channeling? DO i need to stir more? I'm tempted to go back to a pure batch-sparge method to totally drain the cooler and refill with fresh hot water twice to rinse the grains more thoroughly.

 

[iijakii]

Well first off, feel free to just boil a little longer to nail your OG instead of aiming for the same volume.

But give us some more info. What's your mash and sparge process like - in detail? Is your deadspace minimzed? Leaving any wort behind can really effect things.

 

[Ski12568]

Was there a change in your crush at all?

 

[Genuine]

Have you tired going to some sort of recirculating mash system? Ever since I made my Mini eHerms system my efficiency has shot up in the higher 80's. Since being able to keep my mash temp and keep the wort clearing, it has helped me a ton and consistency is huge.

 

[andrewmaixner]

I've been getting similar efficiency for my light beers, single-infusion batch sparging. My stouts get 85%, so I believe it's a PH issue.
I'm going to start with Bru'n Water, RO water and mineral additions to fix that, hopefully.

 

[jgers]

As for correct volume vs correct OG... I'm not taking my preboil gravity so I dont get the bad news until we hit the fermenter. Is it possible to do this without a refractometer? Is a regular hydrometer going to work properly at such a hot temp?

The mash process has been changing around but here is what i did on the latest batch in detail:
17 lb grain in 10 g round picnic cooler - mash in 6 gal to 144 for 35 min (was lower than plan so jumped faster than planned to 2nd rest)
+1g boiling water to 154 for 25 min
+1g @190 to 159 mash out, stir (i know this was low but was afraid to use hotter water for my "slow" sparge)
6 gal fly sparge with 190 untreated water at about half-flow rate of the MLT valve.
Yielded about 10.5-11 g preboil for 8.5g batch.

Previous batches typical of previous process (similar efficiency) looked like this:
14.5lb grain + 5.5g water for 1st mash rest @148 45min
+1g boiling to 157 for 15 min
+4.5 gal near near boiling, intermittently added to MLT as it drained at full flow, yielding 8.5g preboil for 7.5g batch

As for the grain crush - yes i had issues with the latest batch due to 2# of grain i toasted my self and crushed with a rolling pin - but even discounting this heavily (estimating 12 gravity pts per # instead of 36) i still get 66% efficiency (using OG! not the lower preboil gravity)

 

[jgers]

Have you tired going to some sort of recirculating mash system? Ever since I made my Mini eHerms system my efficiency has shot up in the higher 80's. Since being able to keep my mash temp and keep the wort clearing, it has helped me a ton and consistency is huge.

I used a brew on premise system a few times with a recirc mash and yes the efficiency on that system was 85-95%. My cooler is great for retaining heat but I do suspect that I have an issue either with channeling / some grain not getting fully rinsed or maybe there is an issue with the mashout / sparge temp? I wonder if recirc/vorlauf by hand could help at all - just upgraded lots of gear so pumps are not in the cards right now...

I've been getting similar efficiency for my light beers, single-infusion batch sparging. My stouts get 85%, so I believe it's a PH issue.
I'm going to start with Bru'n Water, RO water and mineral additions to fix that, hopefully.

Does pH affect efficiency?

Thanks guys for all the help!

 

[Chadwick]

pH has a huge effect on efficiency. If you are doing everything right but the results are still wrong, start looking into the scientific details. pH is a good place to start.

 

[seagondollar]

2 things i did that got me up to 77% from where your at currently was my own grain mill set at .037, and a false bottom. Although, the grain mill is the most effective in increasing efficiency from my experience. I found out recently that my LHBS was just "eye balling" their mills gap, which made sense, since i was only getting in the low 60's using their mill.

 

[acidrain]

I'm not understanding why you don't measure your mash efficiency. That's where the rubber hits the road.
What are your losses? Do you whirlpool and subtract for trub losses?
If I were you, I would go back to basics and carefully measure pre-boil volumes and gravity. Your measurement need to be absolutely accurate.
BTW, are you using a refractometer, or a hyrometer? Are you cooling your samples to the calibrated temps?
How are you measuring volumes?

 

[andrewmaixner]

Originally Posted by andrewmaixner View Post
I've been getting similar efficiency for my light beers, single-infusion batch sparging. My stouts get 85%, so I believe it's a PH issue.
I'm going to start with Bru'n Water, RO water and mineral additions to fix that, hopefully.

Does pH affect efficiency?

Following on Chadwick's answer of "yes": yes, and dark roasted grains, plus the addition of gypsum(calcium sulfate) generally lowers the PH (more acidic) and is used to replicate the english stout styles.
My water is more basic, so I'm interpreting my results to mean that my pH is too high (basic) and is lowering my efficiency on light styles.
See the first chart on this page: http://www.howtobrew.com/section3/chapter14-1.html
and buy the book if you haven't. It's 95% good information (a few things have been shown to not matter in a measurable amount, like racking to secondary on regular strength beers) and will help with your understanding of the general principles of brewing. I read it before I brewed my first batch, though that may be an extreme -- I'm a engineer.

 

[augiedoggy]

pH has a huge effect on efficiency. If you are doing everything right but the results are still wrong, start looking into the scientific details. pH is a good place to start.

On my last brew, I decided to use RO water and treated in with the appropriate minerals and lactic acid to bring the ph down to 5.2 (I have a cheap $8 digital ph meater from ebay).
In the past I used the ph5.2 buffering solution sold in the brew stores which only brought my ph down to about 6.2-6.5 anyway I got a large jump in efficiency on this last brew, well into the mid 80s percentage when doing this so I know it has a large impact...
I have also read darker grains will aid greatly in lowering ph... the beer I was making was a smoked ESB and had no dark roasted grains.

 

[thekraken]

As for correct volume vs correct OG... I'm not taking my preboil gravity so I dont get the bad news until we hit the fermenter. Is it possible to do this without a refractometer? Is a regular hydrometer going to work properly at such a hot temp?

I use a hydrometer. Just collect a 1/2 cup or so of your well mixed runnings, pour it into a cake pan or something to maximize the surface area, put in the fridge for a few minutes and it will come down to the proper temp very quickly. Because this is preboil you can just throw the sample back in the kettle after you take your reading.

 

[andrewmaixner]

I use a hydrometer. Just collect a 1/2 cup or so of your well mixed runnings, pour it into a cake pan or something to maximize the surface area, put in the fridge for a few minutes and it will come down to the proper temp very quickly. Because this is preboil you can just throw the sample back in the kettle after you take your reading.

You can use a calculator to adjust for temperature also: http://www.brewersfriend.com/hydrometer-temp/
my cell phone beersmith app has it built in to the tools section also.

 

[tootal]

The things that affect efficiency are malt crush, mash temp, mash time, alkalinity (ph) and sparge temps and time.

Your mash times could be a little short if your crush is too large. If you can't change your crush then add more time to your mash.

Definitely check your ph. If using mostly light grains then try to start out with your hot liquor around 5.8. If using dark grains then 6.0 is a good starting point. Check during the mash and see if you have dropped to the lower 5's.

 

[thekraken]

You can use a calculator to adjust for temperature also: http://www.brewersfriend.com/hydrometer-temp/
my cell phone beersmith app has it built in to the tools section also.

Yep, there's that too. Personally I worry about thermal shock on the hydrometer or warping my plastic hydrometer test tube so I cool it down first anyway.

 

[jgers]

I'm not understanding why you don't measure your mash efficiency. That's where the rubber hits the road.
What are your losses? Do you whirlpool and subtract for trub losses?
If I were you, I would go back to basics and carefully measure pre-boil volumes and gravity. Your measurement need to be absolutely accurate.
BTW, are you using a refractometer, or a hyrometer? Are you cooling your samples to the calibrated temps?
How are you measuring volumes?

So yeah this will be the next step for me. Right now I use a hydrometer and use the calculator to adjust for temps but have not done gravity measurement at preboil since I have been afraid to test my hydrometer and sample tube with the hot wort. I like the fridge chilling idea but of course this means checking it after mashing is done. (Altho worst case i guess i could rinse the grains a little bit more and add it back if the readings were too low, then boil off more water later.)

What do you do to measure losses at the end of the boil? I guess I could just dump the leftovers into a big heat resistant measuring cup? For this last batch I just made an estimate and added that back into my efficiency calculation.

On my last brew, I decided to use RO water and treated in with the appropriate minerals and lactic acid to bring the ph down to 5.2 (I have a cheap $8 digital ph meater from ebay)...I got a large jump in efficiency on this last brew, well into the mid 80s percentage when doing this so I know it has a large impact...

When you say appropriate minerals do you mean gypsum? or something else?

The things that affect efficiency are malt crush, mash temp, mash time, alkalinity (ph) and sparge temps and time. Your mash times could be a little short if your crush is too large.

Why does mash time affect efficiency? I know mash time affects fermentability but what is time doing for the efficiency? making the carbs more soluble?


Last question - how do you minimize losses in mash tun, such as the space under the false bottom? Is this even worth it to worry about?

 

[acidrain]

That's the thing... why even worry about your losses... make a slightly bigger batch for a few pennies more.
Personally, I get a consistant 75% mash efficiency, and drop to 60% brewhouse efficiency. I use keggles and have large amounts of loss, but I'm OK with that and just adjust my equipment profile if Beersmith accordingly.

BTW, unless you are cooling samples down to at least 100F, the temp compensation calculators are worthless.
Guessing at your volumes isn't helping either... get a good 1 gal. measuring cup (restaurant supplies) and calibrate your equipment.
You may not be as far off as you think.

 

[peterj]

Where are you getting your grains crushed? Grain crush is by far the most important factor in efficiency. It sounds like you don't have a mill, so I would assume you're getting them crushed at your lhbs. Homebrew shop crushes are usually pretty coarse so 65-70% from a lhbs crush sounds very normal.

There's a couple things you can do. Either buy a grain mill and start crushing your own grain with a more narrow gap or just adjust your recipes to a 65-70% efficiency. As long as you are getting a consistent number you can consistently formulate recipes and hit your gravities. The difference in extra grain between 65% and 75% efficiency is not going to make much of a difference on a small homebrew scale.

Looking into water chemistry and mash pH is a good idea though. And it could help your efficiency a bit, but I would definitely start with grain crush. Here are a couple of good links for that:
https://www.homebrewtalk.com/f128/brewing-water-chemistry-primer-198460/
https://sites.google.com/site/brunwater/water-knowledge
http://www.brewersfriend.com/mash-chemistry-and-brewing-water-calculator/

 

[tootal]

Why does mash time affect efficiency? I know mash time affects fermentability but what is time doing for the efficiency? making the carbs more soluble?

The longer you mash the more starch is converted. If your malt is crushed to talcum powder it will convert much faster than if it's just cracked open and two pieces. The coarse mash will take longer for the enzymes to reach the large pieces. This is always the conflict when you buy a malt mill. You want fast conversion but you don't want it to stick so you have to experiment and see at what dimension it sticks and then back off a little. That's one reason why BIAB is popular, you can mill a little smaller, convert faster and you don't have to worry about sticking!

When in doubt do an iodine test. Get a white bowl or cup, put a little wort in the bottom. Barely enough to cover the bottom. Put a drop of iodine in it. If it gets darker, purple to black, you still have unconverted starches. If it doesn't change color then you're good. Rinse the bowl/cup out as iodine is poisonous.

 

[jgers]

So as a follow up - I brewed my last lager of the season this weekend and saw a HUGE jump in efficiency to 85% - the most I've ever gotten at home. Thanks for all the tips.

Here is what I did differently:

1. My first decoction - i loved watching the liquid thin out and clarify - i felt like I was really getting the whole idea of what happens in mash out
2. 2 hour total mash/lauter time (not totally by design but a lot because I was bottling during this time) - 85 min at ~141, ~15 min mashout at 161 with decoction returned, ~20 min to lauter and sparge
3. added 1 package of brewing salts to my sparge water
4. went back to batch sparging - completely drained the mash tun before adding any new water. I think this helps to really fully rinse the grains and also to let the sparge water warm up the grain vs the slightly cooler 1st runnings.

Not sure yet which of these had the most effect but very proud to be moving a big step in the right direction! Cheers to all that added to the thread.

 

[Urkelbot]

I generally get low efficiencies as well. I've been doing double and triple decotions for lagers and the efficiency goes way up.