Parti-gyle with a BIAB

[BitterSweetBrews]

Recently, I have been enjoying the ease of BIAB in my 15 gallon electric boil kettle with a steamer shelf above the element and a custom grain bag. I am planning to do a 5 gallon batch BIAB Imperial Stout. Given the large grain bill, I would like to do a parti-gyle with it. In the past I have just done them normally with a 3 vessel process.

I am going to be using about 22 lbs of grain, around 20 lbs of it will be contributing sugars. I usually get between 74-80% effenciency, as I continually recirculate.

I have looked for information on how to calculate the amount of water you can expect to need for the 2nd runnings but haven't really found any. I will probably add some additional fermentable grains.

My initial thought was to BIAB the Imp Stout, then move the grain bag to my mash tun, which is the same size as my boil kettle, then mash the 2nd batch normally with 4-5 lbs additional 2 row and a minimal amount of additional water. I would probably then just fly sparge until the runoff goes down to 1.010 SG.

Does this sound like a good plan? Is there an easier way? If I could figure out just how much water I need the 2nd time, I could add the full amount in the Mash Tun and just pull the bag when the mash is done. I am conscious of the possibility of tannins from the first batch grain hulls if I mash too long. I could do a separate mash of the additional grains and sparge the used grains with it.

Thoughts? Am I over thinking this?

 

[bionut]

If the pH and temperature are in the right intervals you can't extract tannins, it's not possible.
I would go with the sparging method and watch closely the runoff gravity. Don't know how to calculate the needed water to add.

 

[kevin58]

This may or may not help but your plan sounds right. I did my first partigyle not long ago and I didn't worry too much about water volumes. The first mash was my main concern so I calculated the strike water so that I ended up with enough volume for a 5 gallon batch. Then for the second runnings I just over filled my HLT and sparged until I had the boil kettle volume I needed.... while watching the gravity of course. I believe I ended up stopping at about 1.010 or a little higher.

From what I've read it the ph you have to watch when avoiding tannins. I forget the exact ph number but I remember that when your run off gets to about 1.008 is when you are at risk.

This isn't related to your question but I have copied and pasted some instructions I used to calculate OG's. I believe I got this from searching this or another forum...


If you want to do a 50/50 split Partigyle take the decimal part of the strongest beer's OG and divide by 2. Then subtract that from the OG. Let's say you want the 1st beer's OG to be 1.088. The second beer's OG is 1.088-(.088/2)=1.044

to calculate the full 10 gallons OG add the two OG's & divide by 2. (1.088+1.044)/2 = 1.066. Use 1.066 for your target OG for a 10 gallon batch.

For the SRM you can use .4 as a multiplier and be real close. Say for your 1st beer you expect an SRM of 35. The second beer's SRM will be about 35*.4=14.

You can adjust OG's by blending the wort. If you want to leave the 1st beer as is but want a higher OG for the 2nd beer you can cap it with some grain when you sparge or add DME or LME. Same for SRM. If you want a darker SRM for the second beer just cap it with some dark malt when you sparge.

Batch sparging works great for Partigyles because you have the 2nd runnings available shortly after the 1st runnings so you can blend & start boiling right away.

Here's Mosher's article that has links to the tables. http://brewingtechniques.com/library/backissues/issue2.2/mosher.html

Hope this helps... Cheers!!!

 

[BitterSweetBrews]

I think I am leaning towarda doing the biab first and a separate mash of some additional 2 row then mixing the grains together and fly sparging tiil the gravity is around 1.010.

 

[doug293cz]

If we assume 100% conversion efficiency, 22 lb grain bill, 6.5 gal pre-boil volume, 5.5 gal post-boil volume, and 0.1 gal/lb grain absorption (typical of well drained, but unsqueezed BIAB), then we need 8.7 gal of strike water, the pre-boil SG would be about 1.078, and the OG would be about 1.092.

If we then parti-gyle the spent grain with 2x batch sparges of 3.25 gal each, we will get 6.5 gal pre-boil of about 1.031 SG, and boiling down to 5.5 gal would give an OG of about 1.036.

Of course, if conversion efficiency is less than 100%, then the SG's will all be proportionately lower.

Calculations were done by running a couple scenarios with this spreadsheet.

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