Fess up Time; Can't Get OG on Target

[punkin]

Background is that i've been brewing allgrain for a year and a half or so. Doing 84l batches pretty often.

My old mash tun i ended up setting my efficiency at 74% and hitting numbers every time within a point or so.
New mash tun (esky with brass manifold built as Clive recommendation) was hitting 80%.

About 6 months ago i had a brew that fell 6 or 8 points under the og from the kettle temp adjusted.
I reset my efficiency doen to 70% and it seemed alright, but then every brew would fall below the mark, sometimes 4 points or 6.

I've tried different alcometers, setting the grain crush higher or lower etc.

A couple of brews ago i thought i finally had it pegged, that i was getting too much beer into my cubes and still had a fair bit left in the kettle, i wasn't boiling hard enough.

Brew before last i boiled at a big rolling boil just under foam up and it was fine, 70% but i can live with that.

Last brew i tried to brew a lighter ale at just 4.5%. It was suppossed to be 1045 og and i measured temp corrected 1037.

I'm at my wits end. I'm sure my crush is good, i ran a coarser crush through twice last time. My sparge and runoff is slowish but steady, my boil is good. I'm using brewmate and it all went like clockwork before.
I'm using two thermometers, a calibrated one mounted low in the mash tun that i find a little unreliable as the mash sits around it and seems to be hotter in the corner where it sits and then colder when the sparge water is in there. And a good quality American probe type electronic thermometer floating on top that i take most notice of.

I'm getting around the right amount of wort to my settings, i have a strong boil, i just don't have any more ideas and think i need some help from some more experienced guys who may have seen or heard this problem before?

 

[hoppy2B]

G'day punkin,

First thing I would do is boil some water and check your thermometres by placing them in the water the same way they would sit in the mash to see if they are working correctly. You can also put them in ice water to see if they are reading zero correctly, but usually the boiling water method will tell you straight away if something is amiss.
I had a problem with efficiency a while back and it turned out to be the thermometres. I just use a normal spirit type thermometre inserted fully into the mash. I think they're supposed to be used just with the bulb part inserted. Anyway, as a consequence I was reading temp maybe 5 degrees higher than it was and getting poor results. Obviously my results would have been a lot worst than yours but a degree or two can make all the difference.
You didn't mention what temps you're mashing at. If you were mashing at 63 for example and you were 3 degrees out it would have a massive impact on your efficiency.

 

[QldKev]

With your crush, are you using a drill or a constant speed of a motor?
Do you do any water corrections?
When you say the correct amount of wort, does this include the post-boil volumes as you also mentioned too much wort left over?
Can you post the grain bill and volumes for the 1.037 brew. Maybe it's a calculation issue.
What is your sparge procedure?
When do you stir the mash?
Are you performing any temperature steps, how fast is your recirculation, what pump and how open are the valves.
What was your mash schedule?

 

[Spiesy]

pre boil gravity should be used to check for efficiency, which has nought to do with boil off rates... unless I'm missing something here.

 

[punkin]

Thanks Hoppy, i thought of the thermometers (i usually just mash at 66 but occasionally at 65 or 67) and tried adjusting temp target in brewmate, but it didn't make any difference to the og?

With your crush, are you using a drill or a constant speed of a motor?
Do you do any water corrections?
When you say the correct amount of wort, does this include the post-boil volumes as you also mentioned too much wort left over?
Can you post the grain bill and volumes for the 1.037 brew. Maybe it's a calculation issue.
What is your sparge procedure?
When do you stir the mash?
Are you performing any temperature steps, how fast is your recirculation, what pump and how open are the valves.
What was your mash schedule?

I use a drill, the setup has been the same all the way through.
no water corrections
including post boil i have that sorted
single batch sparge at 75 as brewmate tells me to
once at halfway after mashing in, again when sparging
no temp steps except mash out, i'm a simple man with simple tastes.
60 min mash always.

 

[punkin]

I didn't do a preboil check as i thought i had it sussed. It was the preboil check that led me to the hotter boil conclusion that seemed to fix the issue, or at least get me back up to an acceptable 72%. I can't keep running at 59%.

 

[JaseH]

Pre boil gravity should tell you your mash efficiency - into the fermenter OG will tell you your overall system efficiency. Beersmith gives me mash efficiency based on pre-boil gravity as well as overall system efficiency based on fermenter OG and volume. This might help you narrow down where the problem is?

 

[QldKev]

I find a drill for a mill motor to be a hit and miss. I know a lot of people love them. I did use a 550rpm with trigger speed drill for about 18months before swapping to a motor.


On your brewhouse calc it says actual vol in kettle = 84. I though you wanted an 84L batch, and you allow deadspace, so that vol should be set to 89L. (89L is allowing for your 5L losses, which is pretty high)

59% is your brewhouse eff% (using the wrong numbers),
With 89L and 1.037 you get 64.6% brewhouse eff%



People on AHB talk mash eff%. Mash eff% is always higher than brewhouse% as it does not allow for losses in the mashtun and kettle.


So the 2 numbers you need for mash eff% are
pre boil vol = 102.8L
pre boil gravity = 1.034 (approximated from your boil off and FG)
Results in the mash eff% at 68.6%

 

[stakka82]

single batch sparge at 75 as brewmate tells me to
once at halfway after mashing in, again when sparging

I may be reading this wrong and I've never had a 3v set-up so could be barking up the wrong tree, but you sparge half-way through the mash?

 

[bum]

He's talking about stirring.

 

[brewtas]

no water corrections

A high or low mash pH will reduce your efficiency. It's especially a problem on the high end. A sudden loss in efficiency like you've experienced 6 months ago could be due to changes in your water supply.

Brew before last i boiled at a big rolling boil just under foam up and it was fine, 70% but i can live with that.

Last brew i tried to brew a lighter ale at just 4.5%. It was suppossed to be 1045 og and i measured temp corrected 1037.

It sounds here like you brewed a darker beer that had a higher (although not ideal) efficiency and then a pale with worse efficiency. If I'm reading that right, it would fit with a high pH being your problem. Darker malts would help lower the pH and improve your efficiency.

You could get some acidulated malt and experiment with adding some (up to 3%) to your mash and see if that improves things.

 

[punkin]

Mill is the same i've always used. I have been using flowers a lot lately, but never found that a problem in the past.
I don't really care to learn about the actual efficiency and how it works, that hurts my head everytime i look at it, all i want to do is be able to predict and control the alcohol content of my beer. I want to do that using a moderate rather than a great amount of grain, so that's why i used the efficiency figures.

What's important to me is chucking in the OG in the recipe design stage and having the beer hit that number on brew day. And that is what used to happen with the parameters like deadspace etc that i have in there.

Ph seems to be dead around 5.5 to me.




I don't know if that's good, bad or indifferent, but i do have a small amount of acidulated malt here.

Going back through my files from now to early this year i get;

mid, 2/9/13 predicted OG= 1045 actual = 1037
simple wheat predicted = 1052 actual = 1047
black ipa predicted = 1065 actual = 1055
speckled hen 27/6/13 predicted = 1054 actual = 1055
10 min ipa predicted = 1060 actual = 1063
fly blown belgian 6/6/13 predicted = 1055 actual = 1055
smurtos golden 15/5/13 predicted 1045 actual = 1046
red ale 19/4/13 predicted = 1048 actual = 1051
vic smash 14/4 /13 predicted = 1054 actual = 1058
smurtos no og recorded
10 min ipa predicted 1050 actual 1040
nelson summer ale predicted = 1046 actual = 1040
evil twin 5/2/13 predicted = 1060 actual = 1060

so it's all over the shop. Over is just as bad as under for me, as i get shitful looks and comments about 'too strong' -_-

I could really use some help on this, it doesn't seem to line up with using flowers, i've often made beers that are correct or over be they dark or light at 72% eff (in the way brewmate tells me to calculate it) and had ones that were programed at 60% fail.

I'm at a loss and been trying to figure it out for months on my own.

Last year i was within a point all the time.

I do have a new mash tun, but it has a copper manifold that is designed to palmers design and seems to work very well. As i've said, i've experimented with crush and i'm positive my last crush was good, although the one before it had some whole grains in it, that was the only bad crush i've done.

 

[punkin]

So nobody knows eh?

I'll keep plugging away i guess.

 

[Yob]

hay you checked final rin off gravity when you are at volume? Not leaving some behind with a faster run off or something? Batch / Fly?

Were you having the eff. difficulties prior to changing the manifold?

:blink:

 

[AndrewQLD]

A high or low mash pH will reduce your efficiency. It's especially a problem on the high end. A sudden loss in efficiency like you've experienced 6 months ago could be due to changes in your water supply.


It sounds here like you brewed a darker beer that had a higher (although not ideal) efficiency and then a pale with worse efficiency. If I'm reading that right, it would fit with a high pH being your problem. Darker malts would help lower the pH and improve your efficiency.

You could get some acidulated malt and experiment with adding some (up to 3%) to your mash and see if that improves things.

This is a really good point, unless I adjust my mash PH and sparge PH my efficiency into the boiler will be down by up to 5%. Although 5.2 is a great product for some water supplies it won't do the job so an acid addition of some sort is the way to go.
I know this is a stupid question but in your PH test above is that mash liquid or water? it looks like water. Have you checked your mash PH?

 

[punkin]

No that's water, i figure that water is what's being questioned. After all it used to work with town water and we DO have two supplies from two different dams that are used at different times of year and it is treated differently in summer (ie carbon filtered to remove blue/green algae).

I'm guessing that doing the same recipes with the same grain and water will result in the same PH? If the PH is to change with the grain and recipe being the same it must be because the water PH has changed?


Yob my OG's are taken when i run off to the cubes, i divert a little hot wort and cool it to 20C.

As to the minaifold, i'm not positive if that was the change or not. I had a 120l Icecool box that was a cubic shape for my fish box in my boat, used a square manifold with it. I changed to a 120l Technicie box that is a rectangular shape and built a rectangular manifold for it. I also changed to no-chill recipes around the same time.

I could try using a regular recipe and just do 20 min hop adjustments to rule out the no chill button, or i could dig out the old setup and old manifold and try a no chill brew in the old esky.

I'd just like a theory before i do any of this that explains the wild swings from 4 points over to 8 or 10 points under. I'd like to know what i did right when i did the brews that hit target that i didn't do later or earlier and i'm fucked if i can see where i'm going wrong. I've been battling this as you can see since the beginning of the year by myself and it's making the idea of a brew day disheartening instead of something i always looked forward to.

 

[AndrewQLD]

You should be testing the mash, not the water before adding grains. If your water has a PH of 5.5 it will lower quite a bit after the grains are added, and it can take up to 15 minutes for your mash PH to stabilize as well. A mash PH of lower than 5.2 can affect your efficiency as well giving you poor results. Check your mash PH and see if it's too low.

Testing the water prior to adding the grains will give you varying results as far as your mash PH is concerned as different grist compositions will effect the mash PH differently.

 

[Screwtop]

You should be testing the mash, not the water before adding grains. If your water has a PH of 5.5 it will lower quite a bit after the grains are added, and it can take up to 15 minutes for your mash PH to stabilize as well. A mash PH of lower than 5.2 can affect your efficiency as well giving you poor results. Check your mash PH and see if it's too low.

Testing the water prior to adding the grains will give you varying results as far as your mash PH is concerned as different grist compositions will effect the mash PH differently.

Zacary!

Screwy

 

[punkin]

Went out and did a brew yesterday with the express intentions of testing the mash and forgot.

Did have some resolution though. After cooling the preboil sample i got 1035 where i should have got 1055. In a complete rage i decided to test the htdro out in water and it read .995

Luckily i have a couple hundred hydrometers in the shed and they were all better than this cheapie, but all read one to two points under.
This gave me a preboil reading of 1048, still down a mile.

Post boil OG should have been 1060 and i got 1056, so adding the two points the hydro seems to be down, i am close, but not hitting the exact number like i used to do.

If i adjust the setting to 72% that should give me the correct OG so long as it's repeatable. Once i have some cubes clear i will brew again. Need to do some fermenting now with all 12 cubes full.

Some pics to help...







Grainbed is 195mm deep





Runoff was at around 5l per minute.

So i'm thinking there is a problem with my crush (looked really good after two runs through, very few unbroken grains and lots of husks) my ph, or my mash temperature.
Temp was designed to be 68C ( Evil Twin ) and i seemed to hit half a degree high and lost about 1 degree over the hour. I know this isn't ideal, but i believe it's practical.

As i said i forgot the PH test (i need some tight range papers or a new kit too, as i'm down to a couple of strips and the other kit i have is 1-14) and i think the crush is good, can be corrected on that though.

 

[manticle]

I'd be looking at mash pH too. Also the mineral content of your water.