Question Regarding Hitting OG and Pre-Boil Volumes - Bit Confused

[Jiffster]

I'm preparing for my 3rd AG batch and I have learned quite a bit so far. Even though I've read a lot on this subject, I'm still having some issues wrapping my head around it.



I realize I need to get my system and process dialed in to hit my targets, but help me out with this....



The numbers/scenario below are hypothetical for the purpose of understanding the process.

Say I'm brewing a 5.5 gal batch and my boil volume calls for for 7.5 gallons(based on my current inputs into Beersmith).



Again, based on my current inputs into Beersmith, it says I need 10 gallons of water. I'm batch sparging with a single infusion so I want to divide into 2 equal voulmes which means I would strike with 5 gal and then sparge with 5 gallons.



OK, here's where I'm not sure (assuming I was even correct with the above steps):



Let's say after mashing I drain my MLT (10 gal igloo) and I end up with 3 gal first runnings. I then add my remaining 5 gal to sparge, vorlauf and begin draining my 2nd runnings.



I hit my pre-boil volume of 7.5 gal and, even though there's water/mash remaining, I stop.



Is this correct or do I keep draining to collect more sugars?



If I stop at 7.5 gal and my pre-boil gravity is low, do I collect more wort?

 

[ballsy]

I'm preparing for my 3rd AG batch and I have learned quite a bit so far. Even though I've read a lot on this subject, I'm still having some issues wrapping my head around it.

I realize I need to get my system and process dialed in to hit my targets, but help me out with this....

Say I'm brewing a 5.5 gal batch and my boil volume calls for for 7.5 gallons(based on my current inputs into Beersmith).

Again, based on my current inputs into Beersmith, it says I need 10 gallons of water. I'm batch sparging with a single infusion so I want to divide into 2 equal voulmes which means I would strike with 5 gal and then sparge with 5 gallons.

OK, here's where I'm not sure (assuming I was even correct with the above steps):

Let's say after mashing I drain my MLT (10 gal igloo) and I end up with 3 gal first runnings. I then add my remaining 5 gal to sparge, vorlauf and begin draining my 2nd runnings.

I hit my pre-boil volume of 7.5 gal and, even though there's water/mash remaining, I stop.

Is this correct or do I keep draining to collect more sugars?

If I stop at 7.5 gal and my pre-boil gravity is low, do I collect more wort?

I BIAB so take this with a grain of salt. Everyone has slight differences in not only technique but also equipment. Thus, everyone learns the tweaks they need to make with their particular system so that with consistency they achieve their numbers. It sounds like with your system you do not need that 10 gallons that beersmith says you do. If you stop draining at pre-boil vol then you will likely miss your OG target, BUT if you achieve your correct OG despite leaving behind some wort in the mash tun then obviously you really don't need to change a thing. However, if you fall short of your OG then clearly you needed the remainder of sugars left in your mash tun. Your other option is to be safe & just collect all of it and if your pre-boil is higher than calculated then just lengthen your boil time (90 minute boil) in order to get a higher boil loss thus ending at your correct post-boil volume. Then the next batch, lower your total amount of water to get closer to the correct pre-boil volume once you have completed the entire mash. It shouldn't take long before you get your system dialed in!

 

[doug293cz]

I'm preparing for my 3rd AG batch and I have learned quite a bit so far. Even though I've read a lot on this subject, I'm still having some issues wrapping my head around it.

I realize I need to get my system and process dialed in to hit my targets, but help me out with this....

Say I'm brewing a 5.5 gal batch and my boil volume calls for for 7.5 gallons(based on my current inputs into Beersmith).

Again, based on my current inputs into Beersmith, it says I need 10 gallons of water. I'm batch sparging with a single infusion so I want to divide into 2 equal voulmes which means I would strike with 5 gal and then sparge with 5 gallons.

OK, here's where I'm not sure (assuming I was even correct with the above steps):

Let's say after mashing I drain my MLT (10 gal igloo) and I end up with 3 gal first runnings. I then add my remaining 5 gal to sparge, vorlauf and begin draining my 2nd runnings.

I hit my pre-boil volume of 7.5 gal and, even though there's water/mash remaining, I stop.

Is this correct or do I keep draining to collect more sugars?

If I stop at 7.5 gal and my pre-boil gravity is low, do I collect more wort?

10 gal seems like a lot of water for a 5.5 gal batch. A more reasonable volume range for a 12 lb grain bill would be 8 to 9 gal. Sounds like your equipment profile may not be set up correctly. You can find information on how to set up your profile here: file:///usr/share/BeerSmith2/help/index.html Items that will affect how much water BS tells you to use are:

Boil Off
Lauter Tun Deadspace
Loss to Trub and Chiller​

These need to be correct for your system in order for BS to calculate accurate water volume. Here's a copy of my equipment profile for BIAB:



Note: if you enter a value for "Lauter Tun Deadspace" (which you should if using a traditional MLT) you should check the box for "Adjust Mash Vol for Deadspace." I have zero for trub loss and deadspace since I BIAB and dump everything from the BK into the fermenter.

Generally with batch sparging, you want to collect all of the wort from the sparge in the BK. If you have excess, then you need to adjust your equipment profile. Otherwise, you are impacting your efficiency by unnecessarily leaving sugar behind.

You want to target equal run off volumes for the initial mash and sparge, not equal starting volumes. The run off from the initial mash will be decreased by the grain absorption and the MLT deadspace (undrainable volume.) Grain absorption for a typical MLT is about 0.125 gal/lb of grain, so a 12 lb grain bill would absorb 12 * 0.125 = 1.5 gal. If the MLT has 0.5 gal of deadspace, then the retained volume would be 1.5 + 0.5 = 2 gal. For 7.5 gal pre-boil, you would need to start with 7.5 + 2 = 9.5 gal of total water. You want 3.75 gal of first runnings and 3.75 gal of sparge runnings. So, you want to use 3.75 + 2 = 5.75 gal of strike water, and 3.75 gal of sparge water.

Brew on

 

[Jiffster]

I'm going to read the posts this evening but I wanted to chime and state that The numbers/scenario are hypothetical for the purpose of understanding the process.

 

[Oginme]

quick troubleshooting chart:

High wort volume/high SG = too much water, efficiency is greater than calculated

high wort volume/SG on target = too much water, efficiency is greater than calculated

high wort volume/low SG = too much water, ? on efficiency

on target volume/ high SG = efficiency greater than calculated

on target volume/on target SG = A WINNER!

on target volume/low SG = water volume good, efficiency less than calculated

low wort volume/high SG = not enough water used, ? efficiency

low wort volume/on target SG = not enough water used, lower than expected efficiency

low wort volume/low SG = not enough water used/ lower efficiency than expected

 

[Kate00]

Stop collecting wort at your pre-boil volume. If there is liquid left, use less sparge water on the next brew. If you run short, use more. however you do it, you will leave some sugars behind, but that's just the way it is, even with fly sparging. If you miss your numbers low, you can adjust with some DME. Off the top of my head, I think its about 8 points per pound of DME for a 5 gal batch. Beer smith is really accurate once you get your results dialed in after a few batches.

 

[acidrain]

Calculating sparge volume is the one think I don't use BS for.
Drain your first running completely, and calculate how much more volume you need for your pre-boil volume.
Add that needed amount to the MLT and stir like it owes you money (per Yooper).
Drain that amount and you will have the exact amount of pre-boil needed.

 

[chumaniel]

I'm going to read the posts this evening

 

[Jiffster]

Lots of great info/advice here folks. Appreciate it!

I will work towards dialing in my system but looking at my equipment profile, I suspect some volumes are too high, like "Trub/chiller" loss and "Fermentor" loss. I suspect those are more like .5 gal each if not less.

I know when I'm done with a boil and have drained the kettle, there is very little solid matter. Mostly liquid.

View attachment ImageUploadedByHome Brew1453472955.269964.jpg

 

[blizz81]

I'm batch sparging with a single infusion so I want to divide into 2 equal voulmes which means I would strike with 5 gal and then sparge with 5 gallons.

I don't think there are any "set" rules here, but I believe it's more common for batch spargers to try to match their sparge volumes (some with multiple infusions) to the first runnings, not to the volume of the strike water. Matching your batch sparge volume to strike water would end up requiring a lot of boiloff for even moderate, but especially bigger beers (where you're striking with 7-8gal) due to grain absorption.


I would advise trying to get your system down calculating volumes yourself before relying on Beersmith, and then if you want, try to match Beersmith up with your results. A sample with a 12lb grist and a fairly common mash thickness of 1.25qt/lb (some people surely mash thinner, you can experiment) and fairly common absorption rate of 0.115gal/lb:

Strike Water: (12lb * 1.25qt/lb) = 15qt / 4 = 3.75gal (+ I add in volume under false bottom here)

Absorption: 12lb * 0.115gal/lb = 1.38gal soaked up by grain
First Runnings: 3.75gal - 1.38gal = 2.37gal
==============================
Target Volume: 5.5gal into fermenter
Boiloff Rate: 1gal every 45min
Boil Length: 60 min
Boiloff Volume: 1.33gal
Preboil Volume: 5.5gal + 1.33gal = 6.83gal

Sparge Volume: Preboil Volume - First Runnings = 6.83gal - 2.37gal = 4.46gal
==============================

Depending on your system, you'll find that you may have deadspace in your mash tun - volume of liquid in the bottom that will be left over after you are done sparging. I would think you would add this volume to your total sparge volume. (I have a bottom-draining keg so my "deadspace" is pretty much nil)

The prevailing wisdom is for maximum efficiency, you want your batch sparge runoffs to be equal volume (ex: http://braukaiser.com/wiki/index.php?title=Batch_Sparging_Analysis ). In this case of a not-huge beer, the numbers almost work all the way around for a double batch sparge: FR = 2.37gal, S1: 2.23gal, S2: 2.23gal. In actuality, the efficiency bump is small enough that most batch spargers simply do one mass infusion.

As you batch sparge with bigger and bigger beers, you'll find there's a point where you cannot maintain the "batch sparge volume around first runnings volume" and your normal preboil volume for a 60 minute boil. This leaves you with two choices: batch sparge with an insufficient volume of water and suffer efficiency, or bump up your preboil volume and boil for longer than 60 minutes.