Beginner Efficiency Troubleshooting

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jbritt

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I have been researching forums and reading homebrew material to try and figure out what is causing my low OG but I decided to just post all the information and see if someone with more experience can give some tips given my particular situation. I recently brewed my second all-grain 5 gallon batch and again the OG was well short of my intention. On the first batch I did not record my information very well and I'm pretty sure lack of mash temperature control was the culprit on that one. In the most recent batch, I brewed an Irish Red Ale with a target OG of 1.058. Mash temperature was pretty consistent at 153 and I mashed for an hour and fly sparged for about 30 minutes. My actual OG was 1.042 which is pretty terrible efficiency and seems like there must be something blatantly wrong. I am wondering if the reason could be that the grains were not crushed enough since it seemed like everything else went according to plan to my knowledge. See other relevant recipe details below:

Maris Otter: 8.52 lbs.
Munich Malt: 1.36 lbs.
Vienna Malt: 1.28 lbs.
Cara Red: 0.70 lbs.
Caramel Wheat: 0.26 lbs.
Roasted Barley: 0.28 lbs.
Total: 12.41 lbs.

Mash Water: 4.03 gallons
Sparge Water: 5.19 gallons

Boiled for an hour and ended with about 5.5 gallons.

Any tips on things I need to be aware of in the future would be helpful. I don't want to end up with another low abv beer!

Thanks
 
Was the recipe set up for 5.5 gallons? If it was only 5, then it would still be a bit short, but still within the margin of error. It's also possible the crush has something to do with it. Did you crush your own or was it a HBS crush?
What was your mash like? Time? Temp? did you batch sparge or fly? What was the pre-boil volume?
 
We need a few hardware details please, did you do anything to the water ie minerals and pH? BIAB or all in one or multi vessel?
Looks like a pretty stiff mash if recirculating, what was your crush like? Did you stir?
@jrgtr42 the op appears to have done this " Mash temperature was pretty consistent at 153 and I mashed for an hour and fly sparged for about 30 minutes. "
 
No I tailored the recipe to 5.5. I crushed myself at a local homebrew supply store but unfortunately did not consider the gap but from memory I kind of remember it being a little on the wide side. I know that isn't helpful but I want to narrow all other possibilities as well to get it all right in the future. Mash thickness was 1.3 and I mashed around 153F for an hour. Fly sparged and pre-boil was 7 gallons.

I haven't gotten into the water chemistry yet...which was another thing I was wondering about affecting OG.
 
30 minutes for a fly sparge is pretty quick...i recently found a cheap refractometer is handy for reading runoff as you sparge, you want to take it down to about 1.010 or so, how ever slowly that is....
 
And 3 pot system not BIAB. I recirculated as well and did stir a handful of times. At the beginning when the grain went in and I would say stirred 4 or five more times after.
 
@jbritt
thats pints per pound is it the 1.3?
I'm an all in one vessel brewer and have found water and crush affect the efficiency, BIAB I understand does much better with a finer crush than all in one.
Are you BIAB?
 
1.3 quarts per pound of grain for the mash. I have seen that as well for the BIAB - and no I don't BIAB.
 
Did it recirculate really easy? Might suggest crush too big.
I started adjusting my crush by going finer for half the grain bill to start with, that way no dramatic effect such as stuck mash/ sparge. Then increased proportion and watched effect.
Even if not into water chemistry half a campden tablet to get rid of the chlorine / chloramine is a must.
 
Super easy recirc. Interesting I will try that with the grain to avoid stuck mash. Ok I will do that as well.
 
I've done a bit of conversion into old figures from the ones I use. My ratio would be about 3 quarts to 2 lb of grain ( 3+ litres / kg ) for the mash.
Every system is different and I have not used a 3 vessel system.
 
Do you think given the information I have that the chunky milling is most likely the biggest reason? Seems like it would need to be something like that to get such a low OG since the mash temp was consistent and water is presumably ok.
 
To really diagnose mash efficiency problems, you need to collect the following data, and volume accuracy is key (best if you correct all volume measurements for temperature expansion back to 68°F (20°C.))
  • Grain bill weight
  • Strike water volume
  • Total brewing water volume
  • End of mash SG (after stirring and/or vorlauf)
  • Pre-boil SG
  • Pre-boil volume
  • Post-boil SG
  • Post-boil volume
With the above data it is possible to calculate both conversion efficiency and lauter efficiency. Mash efficiency equals conversion efficiency times lauter efficiency.

Low conversion efficiency is primarily due to too short a mash time for the coarseness of crush. Coarser crush takes longer to finish conversion. Easiest way to improve conversion efficiency is to crush as fine as you can without causing a stuck lauter. Once you are crushing as fine as your system will allow, then you can extend mash time if you still have low conversion efficiency. Decent conversion efficiency is above 90%, good conversion efficiency is greater than 95%, and 100% is possible.

Poor lauter efficiency is usually due to channeling when fly sparging, or insufficient wort homogenization prior to run-off if batch sparging. Maximum possible lauter efficiency is highly variable, and depends on grain bill weight, grain absorption ratio (if batch or no-sparge), pre-boil volume, and sparging method.

You didn't list a pre-boil volume, so I assumed 6.75 gal (boil-off of 1.25 gal to give post-boil of 5.5 gal.) I then used a triple batch sparge to simulate your fly sparge. Assuming you didn't have significant channeling during sparging, I got your conversion efficiency at about 57%, which is really bad.

So, you should look at finer crush and/or longer mash time.

I used my spreadsheet and "Goal Seek" to do the simulation above.

Edit: I reran the simulation using the 7.0 gal pre-boil volume you posted after I did the first analysis, but it didn't make a significant difference.

Brew on :mug:
 
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I'd add the campden next time, finer milling experiment part of the grains as mentioned above plus if the recipe is designed for 5 gallons then need to boil to get 5 gallons taking account for hop losses and residual. Best I've managed is 83% efficiency, but as many say grain is cheap but it feels bad to me leaving goods behind. @schmurf found his efficiency much higher with overnight mash which fits with the very wise words of @doug293cz .
 
Things to try: if you are relying on the LHBS grain mill, try running the grain through twice. If your mash temp was "pretty consistent" then double check the accuracy of your thermometer (ice bath test) and consider mashing slightly lower to increase fermentability. Also try decreasing the mash thickness to 1.5-1.75 qt/lb. I bet if you did the exact same recipe with these tweaks then you would be closer to your target.
 
@doug293cz Thanks for the info! I'm not an accomplished beer math nerd yet so it will take some time to fully understand all of that. Does your spreadsheet show correction of volumes back to 68F? I am familiar with adjusted to the calibration temp of the hydrometer but not back to a specific temperature.

Regarding fly sparging channeling, I have sparge arms with a spigot in the middle of the pot. During the sparge I noticed there was a dip forming in the middle of the grain bed as the sparge water dripped even with the water in the mash tun being 1.5 inches above the grain bed. Is it better to have several spigots across the entire grain bed or is this normal?
 
@jbritt
I struggle to keep the mash bed covered when sparging and have been getting better efficiency. If you are keeping an inch + above the grains during sparge not sure it would be channelling that much. I'd still look at crush and a longer mash and a change of grist to water ratio, with a bit of water tinkering.
Leave the hardware as it is at the moment.
 
Just a tip. I had bad efficiency (50's %) with a different setup. Besides things like a finer crush, I found my thermometer was actually about 10 or more degrees off. It could be adjusted by turning a nut. I forget which direction I was off. It happens.
 
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