8L kettle for 5L packaged volume - Possible?

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8L kettle for 5L packaged volume - Possible?

Post by LavaChild » 2 years ago

Hello!

First, please let me introduce myself - I am currently a kit brewer (therefore, of course, 5 gallon). This does not suit me because the brew length is too large based on my consumption meaning I brew less frequently and, while still honing my technique, have less-than-ideal brews to drink. The knock on effect is the excitement of variety - the very thing that got me into homebrew - is not something I get with my current brewing given the infrequency with which I brew. The solution that I have come to is to move to small batch size (5L) BIAB - I'll be able to brew shorter lengths more regularly with greater variety. Additionally, the 'clean up' will be reduced which is another factor that impacts my desire to brew at the moment!

I have spent the past few days fully getting to grips with BIAB, the jargon, the methodology, the limitations and the benefits. Despite experience I already have a good knowledge of the all-grain process so as I sit here now I feel very comfortable that I understand (a) the BIAB process and why it is as it is and (b) the BIABacus (at least to the detail of the questions I wish to ask). The calculator has been a god-send - Not because it does anything more (at this level) than I can do by hand but the speed at which it allows me to play with the variables and assess the viability of a brew/equipment is significant - To all those that have contributed, thank you!

So, what direction had I hoped to go for the future? Small scale brews that can be completed on the kitchen gas hob - Using a single gas ring... I don't want to go too ghetto! I had my mind set on purchasing an 8L stockpot with (removable) insulating outer. I figured that I could use this to hold the temperature steady during the mash removing the need for external insulation (as it keeps the set-up tidier) or external heat (which requires using the oven - a no go - or monitoring the temperature over the gas hob for an hour). I wanted 5L out of this to package into a 5L Mini-Keg. Simple? According to the calculator sadly not.

My original hope was that this setup would be sufficient for pure-BIAB for beers of standard gravity (~4.5%), with standard fermentables (1kg) and boil (~60 mins). I'd further hoped I'd be able to do bigger beers or longer boils by dropping to Maxi-BIAB and adding a sparge. I wanted to avoid - or at least minimise - dilutions in all cases.

The 8L stockpot is the largest I can find with the (removable) insulating outer. Dimensions are: 26cm diameter and 17cm height (I understand this gives a 9L volume - Either the measurements I've been given by the seller are wrong [possibly outer dimensions?] or accounts for a headspace... Who knows, but assume 8L please!). If I take this information and use the 'example' recipe as a starting point I put the following (minimal) values into BIABacus PR1.3T (Blank):

Kettle Diameter (AV27): 26
Kettle Height (AV30): 17
Boil for (BP33): 90
Desired Volume into Fermentor (VIF) (BH36): 5
OG (AA46): 1.058
Grams (X55) : 5000
Grams (X58) : 1000
Grams (X61) : 500

This gives rise to numerous warnings:
WARNING: Mash volume exceeds kettle size.
WARNING: Volume into Boil exceeds kettle limits.

The volumes most significant to these are mash volume 11.58 litres and volume into boil 9.48 litres. Significantly there is a loss of 3.41 litres to evaporation - This accounts for over 40% of the kettle volume. Is this realistic? Or perhaps the equation BIABacus uses is less accurate at these extremes of the brew length?

To fix the mash volume limit I have added a sparge (EA67) of 2 litres.
To fix the boil volume limit I have added water after the boil (EA79) of 2 litres [NB, I'd probably add this during the boil given that I'll lose 3.41 litres to that but let's assume it's after the boil for now]

BIABacus does recommend to decrease the water used in sparge and, if that recommendation is heeded, to try and reduce dilution amounts to improve recipe integrity. I can understand this concern - Based on the above numbers 4 litres (of the 10.31 litres of water needed) are being held back from the mash... A little under 40%! (*)

TLDR; The (numerous) literature I've read suggest a kettle 1.3 - 1.5 times the volume required. I require 5L and therefore 6.5 - 7.5 litre kettle should meet this. I thought I'd struck gold with the 8 litre kettle. BIABacus disagrees and with a large amount of modifications I'm still unable to get a 'safe' recipe - let alone avoiding BIAB-Maxi as hoped. Is BIABacus being conservative at this scale or not? In summary - Is there any way I can get away with a 5L small batch in a 8L kettle or should I give up before I begin? I do not want to go much larger that this due to (a) hob-size restrictions, (b) sink-size restrictions (I want to crash-chill so that I can complete the brew in one single session) and (c) storage size restrictions. Of course, I don't want to sink money into this if it's ultimately going to be the failure BIABacus suggests.

Any ideas?

Thanks!

Dan.

(*) This confirms that the problem with this setup is clearly the volume lost to evaporation during the boil. Perhaps my question real boils down to (excuse the pun!) whether I really can expect to see a 3.41 litre loss to evaporation over a 90 minute boil?


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Post by joshua » 2 years ago

LavaChild, I would got with 4L with held, and add 2L before the Boil, and 2L into the Boil (section W)

I would also set the Desired Volume into the Fermenter to 5.5L to get 5L into Packaging, But that is Up to you.

See attached BIABACUS Example.
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Post by mally » 2 years ago

Dan - you are correct that the BIABacus will find it harder to correctly predict scenarios when at extremes (volumes, gravities etc.)

You could always do a trial run with water, for example, boil for X length of time, and WEIGH the vessel before & after, then extrapolate. You can then plug this number into the sheet for more accuracy. However, as always this will vary, and you may have to do this 5 or so times to get an average. Even then, it is only an average and your brew day may differ somewhat.

You could also use a hopsock (I am not sure if you are or not). This will reduce your volume losses, and therefore may reduce or remove your need to do a full volume variation (FVV). In case you missed it, type "Y" in hopsock section G.

You could also just do a brew that the BIABacus predicts will fit without FVV by altering VIF (e.g. 4L instead of 5L). then take every opportunity to compare your actuals to predicted, and therefore, allow you to fine tune the BIABacus to your set up. This will then give you a more accurate picture of what you can possibly achieve in future brews.
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Post by LavaChild » 2 years ago

Thank you for the reply. Some comments/questions based on these and other musings I've had since my original post:

1) In order to use an 8L kettle for a 5L brew length pure-BIAB is not an option. Like it not, I have to go with BIAB-Maxi. Correct? (My reasoning - Forget how I collected the sweet wort, for now, kettle capacity is 8L with at best 7L usable given headspace to avoid boil over, no BIABacus calculation gives me less than 2L loss for evaporation during the boil hence I'm already at 5L before considering any loss to trub, etc. Bigger beers or longer brews and this gets worse. Now consider that is based on being able to begin the boil with a full kettle. Without dilutions and/or sparge there is no way for the kettle to remain full from the mash - loss to grain volume and grain absorption. I don't see it's possible to do a pure-BIAB here).

2) I have read elsewhere on this forum a rule of thumb, that I can no longer find, stating a maximum of 30% of the final volume can be contributed by dilutions. Given even joshua's good idea of 2L before the boil and 2L into the boil that's 4L of dilutions in a 5L brew... Well over the 30%. An issue?

3) I would surely measure the vessel if I purchase it but given I'd *only* be purchasing it for this purpose I'd like to, where possible, establish if there is any viability in its use before purchase.

4) At present I am not assuming the use of a hop sock. Given the small nature of this kettle would I be okay to purchase two bags. Use one for the grain in the mash and one for the hops in the boil? Ideally this will help with the hops being able to move more freely. Is there a risk with a bag inserted during the boil (even if not much, if any, downward pressure will be applied by the hops - the bag being installed only to assist removal and reduce the applicable losses)? Would I need a cake-stand or similar to keep the (near empty) bag from touching the base of the kettle?

5) I will probably continue to set the desired volume into the fermenter at 5L because I intend to ferment in a 5L water bottle... This will already be quite tight if I get a vigorous fermentation. I'm aware that I'll get losses into the packaging which on the face of it could be an issue as I'd like to package into 5L Mini-Kegs however from some searching it seems ~4.5L is advised here if you intend to condition in the keg (which I do - using CO2 for the dispense).

6) Does anybody have experience at using a vessel as small as 8L for the kettle for 5L brews and if so, with real-life experience rather than use of the calculator, was this successful?

7) I measured the kitchen hob and I do not think I can safely use a vessel much larger than this so, down this route at least, it's "this or nothing". Even if I could, to do pure-BIAB for VIF 5L I'd probably want a 15-19L kettle. At that stage things are getting back to the vessel size I'm used to with my 5 gallon kits. Sure, a single 15-19L kettle is *great* in terms of required workspace by all-grain standards but given one of my reasons for giving BIAB a try was the simplicity and reduced clean-up I kind of lose this... At which point I'm doing all the work I'm used to for 5L. So then you think well go bigger and before you know it I'm a million miles away from where I'd hoped to be...

I'm sure I'll think of other things as my mind continues to wander...

Thank you.

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Post by Lumpy5oh » 2 years ago

LavaChild wrote:
4) At present I am not assuming the use of a hop sock. Given the small nature of this kettle would I be okay to purchase two bags. Use one for the grain in the mash and one for the hops in the boil? Ideally this will help with the hops being able to move more freely. Is there a risk with a bag inserted during the boil (even if not much, if any, downward pressure will be applied by the hops - the bag being installed only to assist removal and reduce the applicable losses)? Would I need a cake-stand or similar to keep the (near empty) bag from touching the base of the kettle?
There is a possibility of the bag melting if it is in contact with the bottom of the pot.
I have tried to put the bag back in the pot for the boil to use as a hop filter. I thought that I could just throw the hops in and pull the bag when finished. The problem I had was that the steam from the boil got trapped under the bag and lifted it to the surface of the pot. The hops aren't enough weight to hold it down.
Last edited by Lumpy5oh on 29 Apr 2015, 00:02, edited 1 time in total.
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Post by joshua » 2 years ago

LavaChild, a cake Stand will work very well. BTDT.
I use a 3 Gallon(12L) Cheap Cooking Stockpot, and that works very well for 6L batches.


Lump5oh, If your Mechanical, some Clean Stainless Steel Bolts/Nuts hold down the Bag, and If you have Not Lost Your Marbles(Pun Intended) they can be super Sanitized(heat and/or Chemicals), and really help the Hop bag down and are very easy to clean.

IMHO, YMMV.
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Post by LavaChild » 2 years ago

joshua wrote:LavaChild, a cake Stand will work very well. BTDT.
I use a 3 Gallon(12L) Cheap Cooking Stockpot, and that works very well for 6L batches.


Lump5oh, If your Mechanical, some Clean Stainless Steel Bolts/Nuts hold down the Bag, and If you have Not Lost Your Marbles(Pun Intended) they can be super Sanitized(heat and/or Chemicals), and really help the Hop bag down and are very easy to clean.

IMHO, YMMV.
Thanks for the feedback, joshua. It's interesting you use a 12L pot for a 6L brew... So 200% batch size. If I'm aiming for 5L batches then - by this rule of thumb - ideally I'd go for a 10L pot, instead I'm at 8L. It gives me a little more confidence but I'm still a little way off.

I'm sure you're very busy but if you could take a look at some of the other points raised in my recent reply (even if only yes/no answers) I'd really appreciate the help! :)

Thanks.
Last edited by LavaChild on 29 Apr 2015, 02:01, edited 1 time in total.


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Post by joshua » 2 years ago

LavaChild, the 200% kettle size is the best to use for almost ALL BIAB brews, except maybe 1.080+ Gravities

A 12L kettle is Used by Most Cookers for Soup and Stew, and a Normal StoveTop/Nob should be able to Boil that size Kettle/Stockpot very well.

I do not know if your Made of Money, and I am not familiar with England shipping and Taxes, but Amazon.UK has this 11 Litre stock pot on sale.

http://www.amazon.co.uk/Buckingham-Stoc ... 0049MPIM0/

It probably is Thin and may/probably needs Insulation while Mashing.
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Post by LavaChild » 2 years ago

Hi joshua,

Thank you for replying. Money is not the driving force here and actually the pot you have linked to is significantly cheaper. The reviews for it, however, look very poor and suggest it is thin, poorly made and leaks from the handles. It does not seem it would be a good purchase. None the less, I thank you for linking to it - I had previously considered purchasing a Buckingham pot from eBay because they are so cheap for the size however eBay does not have the same review system that Amazon has and without it I would never have known how unsuitable the pot really is.

Back to the 8L pot - The real reason I'm so 'hell bent' on this particular pot is that it is available with an insulating outer. As a result without any modification it should comfortably hold the mash temperature and be ideal. The volume is the only concern here. Additionally, the price is significantly more than the linked Buckingham pot but I don't mind this 'if it's the right tool for the job'. I have yet to find a larger pot that has an insulating outer - I would need to prepare one myself which is something I'd rather avoid. Unfortunately this is a rather significant interest for me given that I have no other way of maintaining the mash temperature short of manual control over the gas hob, which I am unlikely to be able to hold well. Even the idea of putting the pot in the oven is not available as the lowest level the oven supports is Gas Mark 1 which is 140degC - Far too hot for the mash.

As you can see, while the size of the 8L pot is not ideal it has a number of advantages. These lead me to ask the questions as I have done so above. Of course, if you are aware of another off the shelf solution within a reasonable price range (note that a Braumeister for example would not be in budget) I'd be really happy to hear of it.

Thanks!

Dan.


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Post by joshua » 2 years ago

Dan, if you worried about Outside Insulation, Take a look at

viewtopic.php?f=41&t=2611&p=37506 - "Tun Cosy" pot/kettle insulator for mashing

and

viewtopic.php?f=5&t=491 - How do you maintain mash temps?

and

viewtopic.php?f=67&t=846 - Wind Screen/ Heat Jacket/Insulator for Mashing

and

viewtopic.php?f=53&t=676 - What are you using to insulate your pot?

Keeping Mash temperatures is a Concern for everyone, except for those who use electric and a PID controller.
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Post by mally » 2 years ago

Dan, there are some options for you to consider there. Some of those links Joshua gave I have never seen before, so I enjoyed reading them anyway!

I know you said cost is not an issue, but I would guess that a larger pot & a sleeping bag would be cheaper & get you to where you want to be quicker. :dunno:
However, I am going to presume you are "hell bent" on this 8L pot (do you have a link to it BTW)?
To me it seems you have 2 options going this route;

1. Reduce VIF to suit a FVV brew that fits an 8L pot (or a variation within recommended limits).
2. Do a high gravity brew and dilute it afterwards to meet your VIF.

I would initially choose 1 as it is the safest option.
2 is an extreme and I don't think anybody can give you advise on whether it would work or not. I wouldn't advise against you doing it, as long as you were aware it has potential to produce an inferior product.
Also, doing 2 will cost you more in grain than 1. Again cost isn't an issue, and grain isn't that expensive but you could see efficiencies nearer 50% than 80%. As long as you are aware of that, and are happy with it maybe give it a try? :scratch:
Last edited by mally on 29 Apr 2015, 15:18, edited 1 time in total.
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