Trouble hitting target gravities

[Chris Grubb]

Just started getting a little more serious trying to hit gravities and improve efficiencies. Unless I am calculating wrong my efficiency is very low. 48-55% low.

Yesterday’s OG was 1.055 when Target (according to my Brewer! App) was supposed to be 1.062
The previous brew had grains crushed about a month or a little more prior to use, so I thought that was part of the problem.
I purchased a mill and crushed minutes before I added the strike water.
I am doing 5 gallon batches in a 10 gallon Rubbermaid cooler mash tun.
I tried a lower mash temp and mashed out with 170 sparge water. I stirred multiple times during the mash, and ran off the mash very slowly.
My next step is to check my water ph to see if that is way off.
Any other suggestions to help me improve my efficiency and hit my target gravity?

 

[Genuine]

What efficiency figure are you using for your recipes? Can you post an example recipe? I would look at the crush for sure. Are you batch sparring?

 

[Chris Grubb]

Yesterday’s brew: porter
9.5 2 row pale malt
.75 chocolate malt
1 caramel 40
1 brown malt
1.5 oz fuggle@60
.5 oz fuggle@10
London yeast
Mash 153 60
Boil 60

Pre- boil gravity 1.026
Post boil gravity 1.055

Assumed 72% efficiency for recipe.
4.6 gallons strike water
4 gallons 170 sparge water (batch sparge) to get 6 gallon preboil volume.
I have a cereal killer mill set to middle .50 I think, setting. Went down to between .50 and .25, but that was pulverizing the hull and all.

 

[day_trippr]

An .050 crush is way loose and will be an impediment to efficiency unless you mash for hours. Try around .035...

Cheers!

 

[specharka]

I never judge my crush by numbers alone. Make a determined sensory evaluation of your grist before you dough in. Are there pieces of uncrushed grain? Are the husks crushed, or merely cracked? How much of the grist has turned into flour? Typically you want a mix of particle sizes, with 20-40% of the grist reduced to flour, and zero uncrushed grains.

I’ve found that the optimum setting for my mill (Monster Mill MM2) is a 0.039” gap, wet milled and double crushed. Anything tighter and my mill is prone to stalling; looser gaps don’t crush as much grain per pass. You will get there eventually, but it does take some tinkering around to get it right.

 

[kevin58]

Get a set of feeler gauges. I use a set made for spark plugs. As mentioned above, .050 is too coarse. For traditional mashing I set mine at about .038 (.022 for BIAB). If you don't have a gauge set adjust the rollers so that a credit card just fits in between.

 

[doug293cz]

Batch sparging or fly sparging? What was your post-boil volume? Need these in addition to data provided above to do a more complete analysis of your efficiency.

I also agree with the previous posters that 0.050" gap is way too wide, and will result in low conversion efficiency.

Brew on

 

[Chris Grubb]

Batch sparge, post boil volume almost exactly 5 gallons.

 

[jdauria]

1.026 pre-boil gravity, but 1.055 post boil for a 60 minute boil? Something seems wrong there, usually you are looking at a 10 point difference between pre and post boil for a 60 minute mash. 29 points seems like a lot, even if you had your flame turned all the way up and were boiling the heck out of it. How are you taking gravity readings? With a hydrometer? Are you adjusting for temperature? They are calculated for reading at 60F or 68F, so would need to use a online calculator to adjust. Adding your recipe in Brewer's Friend, at 72% efficiency, pre-boil should be 1.053 and post boil 1.063, that's why the 1.026/1.055 seems way off.

Mill setting is way to wide, try like 0.037.

Sparge water is not warm enough. When sparging, you want to keep the grain bed around 168-170F, which means you need to use 180-190F water usually. I usually use a "mash adjust" calculator in BeerSmith to get my sparge water temp. Sparge water should also be adjusted with lactic or phosphoric acid to 5.5.

With batch sparging, are you draining the cooler first and then adding the sparge water? If so, after adding the sparge water, stir up the grain bed and then let it set again to loosen more sugar stuck in the grain.

 

[doug293cz]

I get your mash efficiency at about 63%, your conversion efficiency about 87%, and your lauter efficiency about 72% (mash efficiency = conversion efficiency * lauter efficiency.) Not quite as bad as you calculated.

Either your pre-boil volume or pre-boil SG measurement has significant error, as to get 5 gal of 1.055 OG wort from 6 gal of pre-boil wort, the pre-boil SG has to be 1.046. It's likely your sparged wort was not totally homogenized with your initial runnings wort, and you sampled from a region that was richer in sparged (lower SG) wort.

Also, to get 6 gal of pre-boil wort from a total of 8.6 gal of brewing water, 12.25 lb of grain, and a typical grain absorption rate of 0.125 gal/lb, your MLT has to have about 1 gal of undrainable volume. This undrainable volume is reducing your lauter efficiency, and therefore your mash efficiency.

87% conversion efficiency is not very good. Your target should be above 90%, and better yet, above 95%. This is where finer crush, longer mash times, and correct pH can help, with crush being the most important.

Brew on

 

[Chris Grubb]

1.026 pre-boil gravity, but 1.055 post boil for a 60 minute boil? Something seems wrong there, usually you are looking at a 10 point difference between pre and post boil for a 60 minute mash. 29 points seems like a lot, even if you had your flame turned all the way up and were boiling the heck out of it. How are you taking gravity readings? With a hydrometer? Are you adjusting for temperature? They are calculated for reading at 60F or 68F, so would need to use a online calculator to adjust. Adding your recipe in Brewer's Friend, at 72% efficiency, pre-boil should be 1.053 and post boil 1.063, that's why the 1.026/1.055 seems way off.

Mill setting is way to wide, try like 0.037.

Sparge water is not warm enough. When sparging, you want to keep the grain bed around 168-170F, which means you need to use 180-190F water usually. I usually use a "mash adjust" calculator in BeerSmith to get my sparge water temp. Sparge water should also be adjusted with lactic or phosphoric acid to 5.5.

With batch sparging, are you draining the cooler first and then adding the sparge water? If so, after adding the sparge water, stir up the grain bed and then let it set again to loosen more sugar stuck in the grain.

Testing gravity with a hydrometer and corrected for the temperature. I do let all wort drain, add sparge water, stir, in about 10 minutes drain again.
I thought 170 was the sparge water temp, but 170 should be the grain temp In the tun?

I will tighten up the mill and raise my sparge water temp and see if that helps things

 

[Hopalong]

Numbers from a computer generated recipe are not accurate due to malt being inconsistent. Don't get excited about it when numbers don't line up.

The roller gap was too wide, but to set the rollers at one setting is impractical. When malt goes through the rollers the sound it makes is an indication of where the rollers need to be set. In a brewery the crusher motor is equipped with an ammeter and the rollers are adjusted to current draw.

"Sparge water is not warm enough. When sparging, you want to keep the grain bed around 168-170F, which means you need to use 180-190F water usually."
Here's the problem, mash out is used only in the decoction method where mash is boiled a few times. In malt there's a type of heat resistant, complex, starch, called amylo-pectin. It makes up the tips of grain. Being complex, starch, it's the richest starch in malt. The rest of the starch is simple starch, amylose. Wrapped up in amylo-pectin is a type of sugar, limit dextrin. A and B limit dextrin are tasteless, nonfermenting types of sugar responsible for body and mouthfeel. Now, what's supposed to happen to the starch is that Alpha is supposed to release limit dextrin from the starch during dextrinization, but the starch is heat resistant and during infusion method brewing the temperature isn't high enough to allow the starch to enter into solution before Alpha denatures and it ends up in the spent mash. It's the small, white particles noticeable in spent mash. When the starch remains in spent mash the beer lacks body and mouthfeel. Turning the starch to dust creates different issues because it requires high heat to stretch out pectin coils in the flour.
Amylo-pectin begins to rupture at 169F, at 169F Alpha is wiped out. During 169, 170F, amylopectin enters into solution when Alpha is denatured and the starch is carried over into the bottle. Something to avoid. The pectin causes beer to gel during storage, the gel floats in the center of the beer and it absorbs protein which appear as brown specs.

A spec sheet comes with every bag of malt because malt is inconsistent. The numbers listed on the sheet came from tests performed on the malt. A person interested in buying the malt uses the sheet to determine if the malt is suitable for making ale and lager or if it's suitable for making whiskey. Malt can be called malt and not make a drop of ale and lager. To make ale and lager with high modified malt, it's highly possible that enzymes need to be added. Malt pH, percentage of protein, level of modification (Kolbach), extract efficiency (which is never higher that 83% with high grade brewers malt), gravity per pound, saccharification length of time, sometimes conversion length of time, are listed on a spec sheet.
When a recipe recommends high modified malt, single infusion, only primary fermentation, and adding priming sugar or CO2 injection for carbonation, the malt lacks an enzyme that from glucose forms, complex sugar, maltose and maltotriose. Without the sugar ale and lager can't be made, but Prohibition style beer can.

 

[Chris Grubb]

Wow! Thanks for that information. That is awesome, although I’m not sure I am smart enough to grasp all that. Maybe my efficiency isn’t quite as bad as I thought, but definitely some room for improvement. I will tighten up my grinds and check my ph when the meter arrives. I’m sure I will have questions on how to adjust my ph when I know exactly what it is. Thanks for the input!!

 

[Chris Grubb]

Another question: is a stainless mesh bazooka tube in my mash tun a more or less efficient method than a false bottom, or does it matter really?

 

[day_trippr]

Best as I can tell from your original post you are batch sparging, in which case it doesn't matter if you use a bazooka, manifold or false bottom.

btw, you really don't need to slow the sparged runnings - you're not fly sparging, you're simply diluting the residual sugars and running that off...

Cheers!

 

[Chris Grubb]

That would save a lot of time. I tried to run it off at a rate that it took me 45 mins or so to drain off the first running’s which was less than 4 gallons, and ran the sparge off almost that slow too

 

[day_trippr]

Yeah, neither of those were necessary, when batch sparging you only need to go as slow as your lautering device limits you...

Cheers!

 

[RM-MN]

Here's a few things to ponder:
1. The gap on your mill is adjustable. That is so it can accommodate different types of filtering. Nobody can say just what your setting must be to achieve the best efficiency. We can say that .050" is too wide and that .010 is too tight. Yours has to be somewhere in between. Try .035. Stuck mash or sparge, it's too tight. No stuck sparge, tighten it a little more. The tighter you can set it without a stuck sparge the higher your efficiency will be.

2. The sparge water temperature does not need to be really high. The sugars are already in the grains, they just need to be rinsed out. Adding cool water to a hot wet mass of grains will result in the water added becoming quite warm. No need to wait with a batch sparge either, just dump it in, stir well, and drain. A double batch sparge will get you more sugars than a single. A triple will also get more but very little more. Wasted effort and time.

3. The most efficient filter isn't a bazooka nor a false bottom. Because the finer you can crush, the higher the mash efficiency the most efficient filter is the one that doesn't clog. We've found that that turns out to be a fine mesh bag. You may have to lift the bag a bit to expose more filter area but it will allow the wort to come out.

 

[jdauria]

I thought 170 was the sparge water temp, but 170 should be the grain temp In the tun?

Yes. I did this wrong for some time myself too. Then I read something in the AHA forums that I think Denny Conn posted... that if you want the grain bed at 168-170, how can you keep it there with 168-170 water? Obviously that's more geared to fly sparging where you are using water for an hour so that the water is cooling AND the grain bed is cooling. With batch sparging, it's probably not as big of a deal since you are draining quickly though, so you can can get away with the water you use.

 

[Chris Grubb]

So to update this thread, I tested my water ph, and it looks to be around 8.3 (well water). With that in mind, what is the best method to correct my ph, and when is the best time to add it? In the mash? In the boil? I assume mash, and putting additions in my strike and sparge water ? How much improved efficiency can I expect from correcting the ph?

 

[doug293cz]

So to update this thread, I tested my water ph, and it looks to be around 8.3 (well water). With that in mind, what is the best method to correct my ph, and when is the best time to add it? In the mash? In the boil? I assume mash, and putting additions in my strike and sparge water ? How much improved efficiency can I expect from correcting the ph?

pH adjusting minerals should be added primarily to the strike water. You may need to add some acid to your sparge water if it has significant alkalinity (enough to bring the pH down to about 5.8 or lower.) Knowing your water pH does almost nothing to tell you how much adjustment you need, because it is really about the alkalinity. If you have pH 8.3 with very low alkalinity, you need very little in the way of added minerals/acid to get the pH into a good range. If on the other hand, you have pH 8.3 with high alkalinity, it will take much larger amounts of minerals/acid to get your pH down. Mineral quantities are relatively small in both cases, single digit grams vs. double digit grams.

The following page is a good place to start learning more about water in brewing: https://sites.google.com/site/brunwater/water-knowledge

Brew on

 

[RM-MN]

So to update this thread, I tested my water ph, and it looks to be around 8.3 (well water). With that in mind, what is the best method to correct my ph, and when is the best time to add it? In the mash? In the boil? I assume mash, and putting additions in my strike and sparge water ? How much improved efficiency can I expect from correcting the ph?

Yes, the mash pH is important and you can expect little change in efficiency by doing so. The primary change in efficiency is in the crush of the grain.

Mash pH is a moving target, one that you have to shoot for before you even know where the target will appear. The mash pH will take several minutes to stabilize but the conversion starts immediately when you add the grains to the water and the pH achieved depends on the mix of grains used with darker grains causing the pH to become lower. Start with improving the milling of the grain. Once you have that done, then adjust pH as it will improve the flavor of the beer more than the efficiency.

 

[Hopalong]

"Wow! Thanks for that information. That is awesome, although I’m not sure I am smart enough to grasp all that."

Yeah, you're smart enough. You made it this far.

High modified malt contains mainly Alpha, pick out a saccharification temperature and there are charts that list the pH that matches the temperature and adjust mash pH to match saccharification temperature.
Type in, Optimum temperature and pH for Alpha amylase, check out Beta, too.
It is better to establish mash pH before enzyme activity begins.

My mashing schedule begins at 95F that's when I adjust mash pH to match Beta because the next temperature step in the process activates Beta. By doing it that way I'm able to adjust mash pH before Beta kicks in. I like to use the rest because Alpha is softening starch at the same time.
My brewing process includes a conversion rest and I establish pH optimum for Beta with sauer malz with mash temperature 140 to 145F. Alpha works fine at Beta pH during conversion.
When using sauer malz the pH varies from 3 to 3.5 and when the malt is 3 pH less is needed than when the malt is 3.5 pH the problem is that you won't know what end of the scale it's on and because of that it's easy to add too much, I learned from experience it's better to add a little at a time before enzymes activate. The purpose of an acid rest is to allow enough time for each addition of sauer malz to stabilize, lacto is active during the rest which reduces pH. Sauer malz isn't needed when the acid rest period is stretched out because lacto will acidulate the mash, the problem with lacto is that it picks up speed and it's best to check pH at regular intervals to make sure that pH doesn't drop outside the range of enzymes.

For experimentation and to gain a baseline to work from I'd take a pound of malt and soak it in the brewing water adding nothing to the water using the same qt/lb ratio used during mashing. Using 60, 65F water and soaking the mash for 15 minutes I'd test pH, and I'd test pH every 15 minutes for an hour rest period to see what happens. Then, I'd do the same thing using water that was boiled, cooled and racked. I'd do it again after boiling the water twice and racking twice and again after boiling and racking the water three times. By doing that I'd find out where mash pH stabilizes with the water and malt that I use, and it would tell me if boiled and racked water would dial in and maybe I wouldn't need to add as much of something.

If possible use RO water and add nothing because enzymes and yeast will not despise you for using RO water. It creates consistency.
An easy to do tip. Before adding hops bring the wort to boiling and as the hot break rises skim it off and continue to remove it until it ceases to form or it drastically reduces, then add bittering hops. Remove the second hot break as it rises. Removing hot break cleans the wort and less hops will be needed because hop character sticks better to clean wort. There will be less goop transferred into the primary fermenter, as well.