Author Topic: negative infusion volume  (Read 1673 times)

Offline Ilovebeer

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negative infusion volume
« on: July 23, 2020, 04:55:40 PM »
I have been around and around trying to fix this and I see others with similar problems but can't understand the solution. I think that the issue might be related to the recoverable mash deadspace which is .92 gal (Grainfather). I started with a single decoction profile and added a temperature step because the recipe called for it. First step is infusion with 1.25 q/lb, all OK. It added the deadspace volume to the mash water volume to calculate the water to add. Next step is temperature, I did not put in water but it filled in water to add -4.1q. I changed it to zero but later it was back. It also changed the water to grain ratio, but I changed it back to 1.25. Error message, can't have negative infusion volume. Third step decoction, again I changed the ratio back to 1.25 and it says add -.88q water. I don't get it...

Online Oginme

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Re: negative infusion volume
« Reply #1 on: July 23, 2020, 05:47:50 PM »
Export the recipe with the offending mash profile as a .bsmx file and post it here.  Once we see how it is set up and being used in a recipe, we can figure out where the issue is and possible solutions.

You can export the recipe by highlighting the recipe in the folder, click on 'file' > 'export selected'.  This will open up a save file box where you can give it a name and save it.  Then attach the file to your next post here.
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Offline Ilovebeer

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Re: negative infusion volume
« Reply #2 on: July 23, 2020, 07:19:00 PM »
Thanks OGinme
Here it is

Online Oginme

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Re: negative infusion volume
« Reply #3 on: July 24, 2020, 06:35:09 AM »
Start by remembering that this is a program which does calculations.  It cannot read your intentions.  So your definitions of steps is critical to the program giving you the correct answer.

In your mash profile, you start with a single infusion for a protein rest.  This infusion contains the volume needed to fill the deadspace at the bottom of your grainfather.  When you gave it the water to grain ratio from the initial infusion, the program calculated out how much water is needed, subtracted the amount of water already in the grainfather and came up with a negative value equal to the dead space volume. 
The next step, you are again calling for an infusion to bring your mash up to saccharification temperature.  BUT YOU ARE NOT ADDING ANY WATER. 

Since you are just bringing the temperature target on the grainfather up to 150F, the step infusion should be entered as 0 in the 'water to add' and the program will recalculate the water to grain ratio based upon the water which is already in the grainfather.  At this point, the calculation does not consider the dead space in the equipment, since that has been covered in the first step.  This will allow the program to calculate the water to grain ratio based upon the information it does have, which is the total water already added.

Recycle your grains, feed them to a goat!

Offline Ilovebeer

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Re: negative infusion volume
« Reply #4 on: July 24, 2020, 12:14:09 PM »
Thanks again for your help. I still don't get it. The first step, infusion, it calculated the water as water/grain X grain = 15.4 Q, but in the instructions, called for the additional 4.1 Q for the foundation. It did not subtract, it added. The second step I entered as a temperature step (not infusion), with zero water added, and with the same water/grain ratio. It changed the water to -4.1 Q and the water/grain ratio to 1.58. I tried changing water back to zero and changing the ratio to 1.25 but it changed it back again. Today I went back and changed the water added to zero, but this time I left the water/grain at 1.58, which reflects the overall ratio. Not sure why it should change  from step 1 to 2, but OK. My third step is decoction, and again I entered zero water, but it changed it to -.88, and it is grayed out so I can't change it.
I would like to understand how to handle this correctly but have not managed to follow the logic

Online Oginme

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Re: negative infusion volume
« Reply #5 on: July 24, 2020, 12:26:34 PM »
Let me walk you through the calculations.  Remember that the program does each calculation separately.

Step 1:  Protein Rest:  you add 2.608 liters of water per kg of grain (sorry my figures are metric) plus the 3.88 liters for the dead space = 18.46 liters of water

Step 2:  Temperature rest:  You specify 2.608 liters of water per kg of grain = 14.59 liters of water.  The program starts with 14.59 liters needed and subtracts the 18.46 liters you already have which gives you an infusion of -3.88 liters.

The solution is to edit your second step and erase the water to grain ratio and enter "0" in the 'water added'.  The program will then take your existing water divided by the grain amount to give you a water to grain ratio of 3.301.

When you advance to the second step, the program does not recognize the dead space volume and configures the mash according to the water to grain ratio you specified.  Instead, just enter zero for the water added and let the program think your water to grain ratio is higher than what is actually in contact with the grains.  Since you have already established this value in the first step, it really does not matter to the program or you process.   
Recycle your grains, feed them to a goat!

Offline Ilovebeer

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Re: negative infusion volume
« Reply #6 on: July 24, 2020, 02:49:32 PM »
OK, thanks again Oginme for sticking with me. So to correct the decoction step with the negative water added, I deleted the step because I couldn't edit it. Then I put in a new decoction step with water zero and no water/grain ratio, and let it calculate the ratio, which was unchanged from previous step. So it all works now