Partigyle Planning Using the BIABacus (An unoffical draft guide)

Post #1 made 4 days ago
[NOTE: This is a very advanced topic.]

I've wanted, for a long time, to write a procedure for using the BIABacus to partigyle. One main problem is that I generally do not brew high gravity beers (@Sarah Sarah has forced me several times) and the grain bill on those done has not lent itself to being re-used for a lower gravity brew e.g. Cherry Chocolate Stout! Since tasting Rocky Ridge's absolutely beautiful Rock Juice, I now have the desire!!!

@lukasfab and I will brew it on Sunday week. Ricky from Rocky Ridge has already given Sarah a few tips and she'll drop in this Sunday to help with the recipe design. (She can't brew with Lukas and I as she's working :dunno: ).

What is Partigyle Brewing? (Very Brief)

I'll use SVA (Single-Vessel All-Grain), i.e. pure BIAB, as the method although the same principles apply for MVA (Multi-Vessel All-Grain). When brewing high gravity beers, a lot of sugar remains in the spent grain. Partigyle started in days of yore to utilise this sugar, a second batch of beer was made from the left-overs of the first batch.

Think of it like this... clean a filthy bath towel in a 5 gallon bucket of water. Lift the towel out, give it a bit of a twist and then dump it in another 5 gallon bucket. Pull the towel out of the second bucket, give it a bit of a twist and then throw it on the floor. What you'll note are the following...

The first bucket of water will be really dirty and there will be a bit less in it because the towel soaked up some of the water and retained it.
The second bucket will be cleaner but will still be dirty and there will be more of it because the towel was already wet when dropped in the second bucket.

In the above analogy, we can think of the dirt as being sugar. The first batch yields very sugary water (high gravity sweet liquor) while the second yields a much lower gravity.

The Dynamics

There are many ways we can play around with our dirty towel and buckets. For example, what if we put the dirty towel in a 10 gallon bucket first and then put it in a 5 gallon bucket. Would both buckets be left with equally dirty water? Or, what about the opposite?

Old hands here know that the BIABacus is the first and only software that auto-estimates kettle efficiency. The existing algorithm is pretty good however it is a linear one whereas, in reality, at extremes, kettle efficiency changes rapidly. For example, put a dirty towel in 1 gallon of water, clean it and pull it out. What is left? A few dribbles of very dirty water. So, you have had almost zero efficiency in cleaning that towel. Put a dirty towel in 50 gallons of water and it is going to be pretty much as clean as if you had washed it in 200 gallons. Anyway until a mathematician puts their hand up we need to stick with our linear formula which does seem to be working really well.

Thinking through the Partigyle Plan Assuming you have come up with a grain bill that will work for both a high and low gravity beer (e'g' an IPA and an APA) the first thing to decide is which batch do you want to give priority too. There are three choices:

1. Aim for a full fermenter of the high gravity brew and get what you can for the low gravity brew.
2. Aim for a full fermenter of the high gravity brew and get what you can for the low gravity brew.
3. Play around with the BIABacus to find a compromise.

In the next posts, I'll explore the first options on how, using the same grain bill, I plan to brew:
- An Imperial New England IPA (9%ABV)
- An American Pale Ale (4.5%ABV)
Last edited by Pat on 18 May 2018, 15:29, edited 3 times in total.
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Option 1 - Aiming for a Full Fermenter of the High Gravity Beer

Post #2 made 4 days ago
With this option, when initially planning volumes and gravities of the partigyle, all we need to know are the

The High Gravity Batch Essentials (e.g. Imperial New England IPA)

In this scenario, the following information is essential for the initial plan....

- 9%ABV
- 19 L / 5 gallons - Volume into Packaging (VIP)
- An approximation of the amount of hops used*
*This recipe is massively hopped so there will be increased KFL (Kettle to Fermenter Losses) and FPL (Fermenter to Packaging Losses).

Setting Up the High Gravity Initial BIABacus

[Note: This file is an approximation of the hop amounts we'll be using - loads! (I'll post the finalised recipes later on.]

First I looked at what gravity I would need to achieve 9.0% ABV:
- High gravity beers tend to attenuate less, so, in Section X, I have reduced the apparent attenuation to 70%
- I then adjusted my OG in section C until the expected ABV% in section A equalled 9.0%. The OG required is 1.100

My desired Volume into Packaging (VIP) is 19 L however, the BIABacus only allows the user to input a desired Volume into Fermenter (VIF) so:
- In Section B, I initially set my desired Volume into Fermenter (VIF) to 23 litres. In Section K, at the bottom, I saw that this would yield 21.3 L VIP. This is more than I need however...
- The current version of the BIABacus 1.3U does not auto-estimate for ridiculous loads of hops. Nor does it allow for the extra trub that occurs in high gravity beers* so, in Section X, I fixed the FPL to 4.0L. (The auto-estimate was 1.75L). This should be enough allowance and so we now have a VIP of 19L + KFL of 4L = VIF of 23L.
- For the same reasoning, I also need to over-ride the auto-estimate for Kettle to Fermenter Loss (KFL). The auto-estimate is 3.83 L however, I am going to increase that to 6L.
* I am working on the next version of the BIABacus which will aut-estimate these for us however, it's quite complicated to do as it requires a goal-seeking formula and, in the past, any time we have used macro formulas, they only work on some platforms unfortunately.

The above over-rides may be too high however, this is unimportant for the sake of this exercise. Although I'll need more grain than if I made the losses lower, if they are lower on the actual brew day, I'll simply get more beer.

High Gravity Partigyle.jpg
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Last edited by Pat on 18 May 2018, 14:44, edited 2 times in total.
Are you a "Goodwill Brewer?" Pay forward and Buy Some BIPs ;)

Option 1 - Aiming for a Full Fermenter of the High Gravity Beer (Part 2)

Post #3 made 4 days ago
Now that we have the High Gravity Partigyle set up, we now need to see what yield we'll get get for our Low Gravity Partigyle

The Low Gravity Batch Essentials (e.g. American Pale Ale)

For the Low Gravity Batch, the essential information we need to establish is, "How much sugar will be available from the High Gravity Partigyle spent grain?"

How Much Sugar Do We Have Available?

From the High Gravity Partigyle BIABacus, we know the following:

We have 14,587 grams of grist. (There is no need to worry about the fact that this grist is now wet.)
The BIABacus also tells us that the Efficiency into Kettle is expected to be 67.1% (Section P). This means that there should be 32.9% of sugars left in that grist.

Setting Up the High Gravity Initial BIABacus

Here's what I've done....

I've saved the High Gravity Partigyle BIABacus file as a different name and then changed the following:

- The name in Section A.First I looked at what gravity I would need to achieve 9.0% ABV:
- The OG in Section C to 1.050 (because, if possible, I'd like to get that gravity).
- I've changed the hop amounts to something more suitable.
- I've deleted the 70% attenuation in Section H
- I've deleted the KFL and FPL over-rides in Section X
- Also in Section X, I've changed the Volume Loss from Lauter to zero because our grist is already wet from our first brew.
- Finally, in Section Y, I've changed the FGDB to 26.32%* and the MC to 4%*

* The logic here is that our original grain bill assumes the grain held %80 sugar and 4% moisture however, the first batch has stolen 67.1% of that sugar. 67.1/100*80=26.32%. (The Moisture content we disregard.)

Seeing what we have so far...

The only thing we need to look at here is the right hand side of Section C. The BIABacus is telling us that we need 16506 grams of grist should we want 23 L Volume into Fermenter.

Low Gravity Partigyle - Pic A.jpg


However, we only have 14,587 grams available. What I now need to do is keep lowering my Desired Volume into Fermenter in Section B until the right hand side of Section C says 14,578 grams. 20.45 L gets us pretty right.

What We Can Expect on Our Low Gravity Partigyle

In summary, we can expect to get 20.45 L Volume into Fermenter of wort at 1.050 Original Gravity and 18.94 L Volume into Packaging.

Low Gravity Partigyle - Pic B.jpg


Things are looking good! As to what will happen in reality on brew day is yet to see :)
I'll let you know finalised recipes and actual results later.
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Last edited by Pat on 18 May 2018, 15:26, edited 5 times in total.
Are you a "Goodwill Brewer?" Pay forward and Buy Some BIPs ;)
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