Missed Gravity again for the third straight time!! Any help appreciated!!

[BigEasy43]

So I am a Rookie and AG and just finished my third batch and missed the gravity again and this is frustrating. This time I did a cream ale with numbers below.

Mash Water 2.83 Gal @ 150F for 60mins
Sparge Water 5.64 Gal @ 168F (Batch Sparge let it sit for 10mins)
Collected 6.5 Gal of Pre Boil Wort
Original Gravity was 1.030, but kit called for 1.044
Final Gravity was 1.004, but kit called for 1.008
Total Grain weight was 8.50LB

I use a rectangle cooler with a bazooka screen and I use kits as I am just starting out. I don't use DME at all as I don't feel comfortable with this and don't take a pre boil gravity reading. Is that one of my mistakes, not take a pre boil gravity reading?? I thought the all grain kits I am buying I wouldn't have to do this?? I feel with this beer as the ABV is about 3.5% is a waste of beer as it such a light beer now and should have been 4.8%. Any help would be great.

 

[brewbama]

I have more success using 1.65 qts per lb for better efficiency. Use more strike and less sparge water to get equal runnings. http://hbd.org/cascade/dennybrew/

From dennybrew:

R1=initial runoff volume which = mash water volume - water absorbed by grain
(assumed to be .1 gal./lb. for this example since that’s the way my system works...use your own figure)

S= batch sparge water volume
V= total boil volume (amount in needed in kettle for boil)
I=volume of infusions for a step mash

R1+I+S(1)+S(2)+S(etc.) must equal V
AND
R1+I=.5V

Also Ck your crush. Finer crush may be required for better efficiency.

 

[SpahrBrewing]

What's your post boil volume? If it's 5g, that's a 23% boil off rate, quite high. Are your boil off rates calculated correctly and in turn your strike and sparge water volumes? If your volume is high, you could be not boiling hard enough, which is fine as long as your boil off rate is adjusted for such. I know that with my 20g pot, I can boil off anywhere between 1.5 and 3 gallons per hour depending on how I have the propane cranked (all still boils).

 

[stonebrewer]

I would take a gravity preboil to see if the issue is in the boil or the mash. I just went through a similar issue after moving to a larger boil kettle. Turns out that the burner was not getting enough oxygen because the new kettle was much bigger in diameter and snuffed out places the burner would get air from with the smaller pot. Not your problem, but I brewed twice without noticing my flame issues. My preboil gravity for the two other beers was perfect, but I was not boiling off enough wort. Your problem will only be resolved when you figure out where it is, and then figure out what is causing it. A preboil reading will tell you where to look, the mash or the boil. Do you get rolling boils? If so, it is likely the mash. Make sure your thermometers are correct!! I have had issues with thermometers more times than I can count. Always double check with a good instant read thermo. Right not my MLT is about 8 degrees low and my HLT is off by 4 degrees. I always use a well calibrated thermo that I trust and use the dials to get into the ballpark. Best of luck!

 

[BigEasy43]

I would take a gravity preboil to see if the issue is in the boil or the mash. I just went through a similar issue after moving to a larger boil kettle. Turns out that the burner was not getting enough oxygen because the new kettle was much bigger in diameter and snuffed out places the burner would get air from with the smaller pot. Not your problem, but I brewed twice without noticing my flame issues. My preboil gravity for the two other beers was perfect, but I was not boiling off enough wort. Your problem will only be resolved when you figure out where it is, and then figure out what is causing it. A preboil reading will tell you where to look, the mash or the boil. Do you get rolling boils? If so, it is likely the mash. Make sure your thermometers are correct!! I have had issues with thermometers more times than I can count. Always double check with a good instant read thermo. Right not my MLT is about 8 degrees low and my HLT is off by 4 degrees. I always use a well calibrated thermo that I trust and use the dials to get into the ballpark. Best of luck!

I just switched over to a Keg to use as my boil pot my last two batches and noticed that it takes much longer to get it to boil. As you know the bottom on the keg is much different and I was thinking when doing this batch that the whole surface is not getting as much heat as a flat boil pot would. So I wonder if this is my issue!!!

 

[stonebrewer]

Could be...you using propane and a banjo burner? Should be plenty hot to make that rock and boil! Make sure your flame is blue and not orange...open the air valves wide open as well as the gas valve. Lotsa folks use keggles so it might be your setup needs tweaking. Take more readings and figure out where the problem is and solve it. One of the fun things about brewing is solving problems, bro!! Cheers!

 

[dmcman73]

So I am a Rookie and AG and just finished my third batch and missed the gravity again and this is frustrating. This time I did a cream ale with numbers below.

Mash Water 2.83 Gal @ 150F for 60mins
Sparge Water 5.64 Gal @ 168F (Batch Sparge let it sit for 10mins)
Collected 6.5 Gal of Pre Boil Wort
Original Gravity was 1.030, but kit called for 1.044
Final Gravity was 1.004, but kit called for 1.008
Total Grain weight was 8.50LB

I use a rectangle cooler with a bazooka screen and I use kits as I am just starting out. I don't use DME at all as I don't feel comfortable with this and don't take a pre boil gravity reading. Is that one of my mistakes, not take a pre boil gravity reading?? I thought the all grain kits I am buying I wouldn't have to do this?? I feel with this beer as the ABV is about 3.5% is a waste of beer as it such a light beer now and should have been 4.8%. Any help would be great.

- You might not be converting all your sugars in the mash. Have you tested this? Really easy to do. Drain some wort from the mash (make sure there is no material in it like grain husks and such). Place a small drop on a white plate (again, be sure there is no material in the drop). Then place one drop of Tincture iodine (you can find this in the drug store, it's a small bottle that will last you a while) right into the drop of wort. If the mixture of a drop of wort and the drop of Iodine turns to a brownish /tan color, you've converted all sugars. If it remains black in color, leave the mash alone for another 15 minutes and then re-test.

- During the end of your sparge you'll want to make sure that the wort you're draining into your kettle never goes below 1.010SG otherwise you start getting off flavors. While sparging, take a sample of the wort right from the mastun drain valve (not from the kettle) and measure, if it's around 1.010, stop sparging and just top off your kettle (if you need to) with fresh water to meat your pre-boil volume.

- Pro-Boil gravity readings are important, you need to know where you're starting off at. If you're not hitting your pre-boil gravity, you may need to change your mashing process. Usually kits give you enough grains to fly sparge. Usually when you batch sparge you'll want to add a bit more grain as batch sparging (according to a lot of brewers) is not as efficient as fly sparging. Don't be afraid to add some DME to build up your gravity a few points.

EDIT: Your grain bill might be a little under as well, can you list exactly what was in the kit? I've seen a number for Cream ale recipes and a good portion of them had a grain bill of a little over 9 lbs or more.

EDIT (Again): Check out this thread, basically goes over more of what I briefly described about batch sparging efficiency: https://www.homebrewtalk.com/showthread.php?t=77125

 

[hottpeper13]

With the info given you are supposed to get ~75% efficiency from that kit. Even if you iodine test completed conversion, if your grain crush is too coarse, and there are whole corns it will look good for conversion but be low in efficiency. I would buy a mill.

 

[BigEasy43]

- You might not be converting all your sugars in the mash. Have you tested this? Really easy to do. Drain some wort from the mash (make sure there is no material in it like grain husks and such). Place a small drop on a white plate (again, be sure there is no material in the drop). Then place one drop of Tincture iodine (you can find this in the drug store, it's a small bottle that will last you a while) right into the drop of wort. If the mixture of a drop of wort and the drop of Iodine turns to a brownish /tan color, you've converted all sugars. If it remains black in color, leave the mash alone for another 15 minutes and then re-test.

- During the end of your sparge you'll want to make sure that the wort you're draining into your kettle never goes below 1.010SG otherwise you start getting off flavors. While sparging, take a sample of the wort right from the mastun drain valve (not from the kettle) and measure, if it's around 1.010, stop sparging and just top off your kettle (if you need to) with fresh water to meat your pre-boil volume.

- Pro-Boil gravity readings are important, you need to know where you're starting off at. If you're not hitting your pre-boil gravity, you may need to change your mashing process. Usually kits give you enough grains to fly sparge. Usually when you batch sparge you'll want to add a bit more grain as batch sparging (according to a lot of brewers) is not as efficient as fly sparging. Don't be afraid to add some DME to build up your gravity a few points.

EDIT: Your grain bill might be a little under as well, can you list exactly what was in the kit? I've seen a number for Cream ale recipes and a good portion of them had a grain bill of a little over 9 lbs or more.

EDIT (Again): Check out this thread, basically goes over more of what I briefly described about batch sparging efficiency: https://www.homebrewtalk.com/showthread.php?t=77125

List of grains below

 

[Bobby_M]

-

- During the end of your sparge you'll want to make sure that the wort you're draining into your kettle never goes below 1.010SG otherwise you start getting off flavors. While sparging, take a sample of the wort right from the mastun drain valve (not from the kettle) and measure, if it's around 1.010, stop sparging and just top off your kettle (if you need to) with fresh water to meat your pre-boil volume.
l]

This has no relation to batch sparging. Second runnings would never be 1.010.

 

[Bobby_M]

Unclear from first post, please clarify.

What temp was the original water? Not 150 right? That's the temp it needs to settle at, not the water temp.

Did you drain all the wort out before adding sparge?

Did you stir aggressively after adding the sparge?

 

[IslandLizard]

Look for a finer crush, that should help with speed of conversion in the mash, and efficiency. Many LHBSs crush rather coarsely. Running through twice is not an alternative for once at the right gap.

 

[BigEasy43]

Unclear from first post, please clarify.

What temp was the original water? Not 150 right? That's the temp it needs to settle at, not the water temp.

Did you drain all the wort out before adding sparge?

Did you stir aggressively after adding the sparge?

The original temp was 162F and it settled at 150F for 60mins

Yes I drained the wort out before adding the sparge and yes I stirred aggressively after adding the sparge and let it sit for 10mins.

 

[Bobby_M]

The original temp was 162F and it settled at 150F for 60mins

Yes I drained the wort out before adding the sparge and yes I stirred aggressively after adding the sparge and let it sit for 10mins.

Ok good so far.

Other things... I would use more water for the mash. As of right now, you have a small amount of first runnings and a large amount of second (sparge) runnings. Based on about 8 pounds of grain, you will lose about .8 gallons to absorption and probably another .2 to dead space if not more. That means the first runnings was only 2 gallons or less.

Mash Water 2.83 Gal
Sparge Water 5.64 Gal
Collected 6.5 Gal of Pre Boil Wort

Since 8-9 pounds of grain will only absorb .8 or .9 gallons, you're losing a lot of liquid somewhere. You used about 8.5 gallons of water and only collected 6.5 gallons preboil. Lets say the grain kept 1 full gallon. Where did the other gallon go? If the tun is using a bazooka, you will leave behind some due to deadspace. You can help this by substantially tilting towards the drain by propping the other side with a 4x4 block of wood. (note that you can test deadspace of the level tun and the tilted tun by putting like 2 gallons in there and letting it fully drain. Measure that amount. Then tilt the tun as mentioned and see how much more comes out).

Now, if you start your mash with say 4 gallons, you'll get about 3 gallons of first runnings and then you'd sparge with another 3.5 gallons to get to your 6.5 preboil.

With batch sparging you can easily go much hotter with the sparge, such as 185F. It may not help efficiency but it won't hurt and you'll be closer to boiling temps as a result.

As others mentioned, your crush may be significantly coarser than you can get away with.

Another possibility is that your thermometer is a little off. If you're really mashing at 147, it would potentially take another 15 minutes of rest to fully convert. A hotter sparge would correct for this but that's not really how to fix it.

 

[Bamsdealer]

You won't get 75% efficiency from one big batch sparge. Break up that sparge into 2 or 3 batches and as stated above, make sure you're boiling off at a good rate.

 

[pricelessbrewing]

Still not enough info to isolate the issue. Without the following information all we can do is guess and make blanket suggestions and hope one of them is correct.

Recipe.

Measured volumes! Without accurate measurements, any calculation is just an estimate.This includes strike volume, first runnings, sparge/second runnings, preboil, post boil, volume into fermenter. Every volume measurement should have the temperature reported as well. Every volume measurement should have the gravity recorded as well.

Alright now that you've taken a bunch of measurements you can 100% isolate the issue to one of the following.

Mash issue, crush/ph is the usual problem although particularly low conversion may also be due to a poor dough in. Stir the hell out of it.

Lathering issue: batch sparge should stir the crap out of it and run off at whatever speed they can without getting a stuck sparge. Fly sparge should exceed at least 200% sparge efficiency in order for it to worthwhile (IMO) as otherwise it's a huge time sink for very little efficiency gain. A good fly sparge should hit 250% or so. It's quite common for a poor fly sparge to get low sparge efficiency in the case of too quick a runoff or substantial channelling. If you're getting batch lauter efficiency when fly sparging, stop and try a batch sparge. Don't forget to stir.

Accurate volumetric inputs. Is your grain absorption accurate? Is your boil off rate accurate? Are you getting a larger loss than you expect from the mash tun or post boil proteins/hops?

 

[dmcman73]

This has no relation to batch sparging. Second runnings would never be 1.010.

Sure it does. Going below 1.010 while batch sparging is not as easy as during fly sparging but it can happen. If you don't have a correct grain bill (not enough grains) and/or over sparge by using too much water to achieve your pre-boil volume rather than topping the kettle off with water, you can go under 1.010.

Again, for the novice and expert, there is never a worry about it...for the beginner AG brewer, it can happen.

Besides, ALL new AG brewers should be measuring everything, including during first and second runnings to get a feel of the entire process and learn how their wort is reacting. They should also be measuring their pH 10-15 min into the mash to start getting a feel of how grains affect the pH of their water so that they can adjust it for future brews if necessarily. By learning this all early on, they'll be better prepared to troubleshoot any issues they can encounter later on.

Just because it's "difficult" to mess something up doesn't mean you can't monitor for it.

 

[dmcman73]

If you are milling your own grains, using a set of feeler gauges, measure the gap of the roller and the "ideal" gap that most brewers use is between .35 and .40. If you don't have a set of feeler gauges, than a quick and dirty way to check would be to see how easy it is to slide a credit card (not the side with the raised lettering) between the rollers. If it slips right through with very little force, it can be set to wide. The card should go between the rollers easily and cause the rollers to turn as well.

As I posted earlier, read through this post on getting the most efficiency out of batch sparging, he hits all the points you should be looking out for and provides good advice: https://www.homebrewtalk.com/showthread.php?t=77125

 

[doug293cz]

To expand on what @Bobby_M and @pricelessbrewing said, I will make some reasonable(?) assumptions about the data that priceless noted was missing, and run a full mash simulation to separate out lautering and conversion losses.

Assumptions: Grain absorption is 0.12 gal/lb of grain, boil off is 1 gal, and your volume and SG measurements are reasonably accurate.

You used 8.47 gal of total water, and collected 6.5 gal of wort (pre-boil). The grain would have absorbed 8.5 * 0.12 = 1.02 gal. That leaves 8.47 - (6.5 + 1.02) = 0.95 gal of volume unaccounted for, and as Bobby said, that is possibly due to undrained wort in the MLT. Your lauter efficiency calculates out to 78.5% (using your strike and sparge volumes.) If you reduced that 0.95 gal loss to 0.125 gal (1 pint), your lauter efficiency would increase to 88.6%. That much undrained wort is a huge hit to efficiency.

Lauter efficiency is maximized by having (nearly) equal volumes for all run offs (initial & sparge.) If you had used 5.22 gal of strike water, and 3.25 gal of sparge water, your lauter efficiency would have gone from 78.5% to 88.4%, a gain of almost 4 percentage points.

To get a 1.030 OG assuming 5.5 gal post-boil, I had to adjust the conversion efficiency in the simulator to 69.5%. This is awful. Homebrewers routinely achieve 95% or better conversion efficiency with good process control. As mentioned previously, coarse crush and pH way out of range will negatively affect conversion efficiency, as will temperatures being off due to uncalibrated thermometers. The best way to monitor conversion is to look at the SG of the wort in the mash (a refractometer is very useful for this.) It turns out that maximum mash SG (100% conversion) is pretty much a constant for a particular water to grain ratio in the mash. You can compare your mash SG and mash thickness to the table here to see how close you are to 100% conversion.

The thinner mash that helps with lautering efficiency will also increase the conversion rate, which can help get more conversion in your allotted mash time (ref: http://braukaiser.com/wiki/index.php?title=Understanding_Efficiency#Mash_thickness.)

If you increased your mash efficiency from 69.5% to 95%, reduced your undrained MLT volume from 0.95 gal to 0.125 gal, and adjusted strike vs. sparge volume for equal run off volumes, your mash efficiency (= conversion efficiency * lauter efficiency) could go from 54.5% to 84.3%!

Brew on

ps: Here's my standard spiel on collecting data for doing a proper efficiency analysis which allows for some consistency verification:

To fully diagnose efficiency issues, the following measurements are needed:

• Grain bill weight
• Strike water volume (everything prior to initial run off)
• SG of wort at end of mash, or first runnings SG
• Sparge process (fly, batch, none)
• Sparge water volume (for each batch sparge if more than one)
• Pre-boil volume
• Pre-boil SG
• Weight & type of any sugar added to the boil
• Post-boil volume
• Post-boil SG (OG)
• Volume into fermenter

Accurate measurements are critical, since the efficiency calculations cannot be better than the measurement accuracy. All volumes should be corrected for thermal expansion to 68˚F, or the volume measurement temperature reported, so that corrections can be made. Hydrometer measurements should be taken with the wort temp within 20˚F of the hydrometer's calibration temperature, and then corrected for the temperature at which the measurement was made.

Mash Efficiency = Conversion Efficiency * Lauter Efficiency
Brewhouse Efficiency = Mash Efficiency * Transfer Efficiency
Transfer Efficiency = Fermenter Volume / Post-boil Volume

With the measurements listed above, all of the factors in the above equations can be calculated. Conversion efficiency should be greater than 95%. Lauter efficiency is a function of sparge process and grain weight to pre-boil volume ratio, and maximum achievable can be predicted (but not as accurately for fly sparge.) Once you know which efficiency factor is lower than what should be achievable, then you know what part of your process needs to be addressed.