Semi-automated Electric Biab

[prestonpaul]

Just a heads up, I have built a similar system using a 60l keg and a 2.4 kw element screwed into a 1" socket welded in to the side of the keg and a cake rack above it to keep the bag off the element. For the life of me, I can not get a whirlpool happening at the end of the boil. I think it is because of all the intrusions at the Bottom of the keg. I also find the boil is not terribly vigorous with the 2.4 kw element so I plan to install a 15 amp outlet and step up to a 3.6 kw element with the lowest watts per centimeter I can fit in to the keg. At the moment I am controlling the mash manually but plan to use a Brewtroller in the future.
I also plan to run some sort of re-circulation but was planning to come in through the side of the keg below the level of the wort so I could also use it after the boil to try and get a whirlpool going. If I was going to do it again I think I would get an element custom made in a circle to run around the keg at the bottom and come in from underneath similar to the Braumeister.

Paul.

 

[TSMill]

PS - the right sort of PID will allow you to throttle your element like a dimmer switch and thus allow you to control boil vigor ... most of the cheap ones don't work that way and you can't control boil vigor with them at all. You can't control boil vigor by temperature... its all isothermal in a boil. So be careful in your PID selection if that's what you want to do.

I was planning on getting one of these PID controllers from Auberins. Will that be suitable for controlling the boil?

The Auberins PID controller uses time proportional control. Basically, it determines the fraction of time the element should be on for, based on the variation between actual and setpoint temperature. Whenever the element is on, the power to it is 100%, there is no "dimmer" function. In manual mode, you can set the fraction of time that the element is on, which will let you adjust for your desired boil vigour with trial and error.

 

[aaronpetersen]

The Auberins PID controller uses time proportional control. Basically, it determines the fraction of time the element should be on for, based on the variation between actual and setpoint temperature. Whenever the element is on, the power to it is 100%, there is no "dimmer" function. In manual mode, you can set the fraction of time that the element is on, which will let you adjust for your desired boil vigour with trial and error.

So does anyone know of a PID that does have a "dimmer" function?

 

[aaronpetersen]

Thanks again TB for another detailed and informative post.
I had seen those concealed crown urn elements before but had forgotten about it. They certainly do look good. I also like the idea that they are 2400W instead of 2200W, which gives me a tiny bit more ooomph. I do think I will still need to regulate the boil though as I often do experimental half batches. Although I think I read a post of your once where you found no difference in boil vigor for different size batches because the vessel surface area is still the same and therefore heat losses will be too.
My original idea was somewhat inspired by Puffer555's rig here. I have since PM'ed him to see if he had any issues with recirc rates and it seems that you were right on the money TB. Here's his response below:

"Everything TB has said are very valid points.
I certainly used to have recric problems with the voile bag.
Now however, If i'm careful, and depending on the recipe, I can get a good recirc going.
It all about starting slow, and gradually (over 10 mins or more) opening the valve mm by mm.
I also use rice hulls every mash to help.
A sight glass connected to the mash tun dead space is an awesome tool for mash recirculation.
On mine, when i start to recirc, the level in the sight glass starts to drop.
This is due to more liquid going into the top of the bag than is coming out the bottom.
A sort of negative pressure in space below the bag.
At the start, I tweak the pump valve so that the level in the sight glass stabilises.
The sight glasses level is lower than the level in the vessel, but when it stabilises, this represents an equilibrium position where the same amount of liquid entering the top is coming out the bottom.
This is usually with the valve only just open at the start.
This then slowly sets the grain bed as a filter.
Rims and Herms users have to do the same thing.
Then, after a minute or two, I tweak the valve again, but only ever so slightly.
When I do this, the level in the sight glass drops again, but I adjust it so it stabilises.
It takes a bit of fine tuning, but over several adjustments, I can get a decent flow going.
It depends on the recipe.
Its important not to shock the mash and compact it, otherwise you'll have to stir constantly to reset the mash.
I will probably be doing some adjustments to my rig soon along the lines of what you have in mind.
One thing i'll be doing is getting a bigger pot, and installing my current pot inside it as the grain vessel.
I'd like to get a full perforated false bottom in the grain vessel, and get rid of the bag - more inline with Braumeister.
Then I can filter during the mash, and when I pull the grain vessel out, I dont disturb the grain bed.
This should mean clearer beers, and also allow a quicker recirc, which should allow better temp control - hopefully."

I'm definitely going to have to think long and hard about how to optimise recirc rates. I'm going to start doing some experiments and LOTS more reading to try to find an approach that works for me.

I'm not saying that you wont be able to get a perfectly acceptable re-circulation rate, just that it will most likely be, as it is in most re-circulating systems, the limiting factor for temp control, ramp rates and the like. I was painting that as an opportunity for you to simplify your wiring needs - not as a problem. Your second element is basically irrelevant for your temp control system - you are safe to ignore it and make your life easier.

I can see that its possible that a system with a bag as well as a false bottom might perhaps be more prone to issues with the mash not circulating easily because the bag isn't the ideal lautering surface - but thats just something to be on the lookout for, its not that it "will" be a problem, just that its a possibility.

You could use the returned wort to "stir" the mash, and if i were building a BIAB re-circulating system, a way to do that would be part of my design... But i am NOT saying that i think its necessary for you to build a successful re-circing BIAB.

As a born and bred BIABer - you need to remember that the bag is NOT part of the mashing process, in normal BIAB, the bag is, or at least should be, entirely irrelevant to the mashing part of brewing, it should only come into play during lautering (ie when you pull the bag out). What you are doing with your re-circulation, is ALL about the mashing process, and basically nothing to do with BIAB. Read the threads about HERMS and RIMS brewing - they will be much more use to you than the BIAB threads. You suddenly need to understand mash tuns, you are about to build one. For re-circulation, flow rate matters, a lot. Think about it in your system design.

That auberins PID - sorry, i dont know. It says it has a "manual control" mode... But whether that means what we are talking about or not I dont know. You will have to discuss it with the seller/manufacturer, or perhaps someone from AHB who has one can let you know. I just wanted you to be aware that not all PIDs are able to control that way and make sure your's could if you needed it too.

Regardless of that, i would be inclined to run with two elements rather than one big one. This (probably) gives you a lower watts per square cm ratio - and thats a good thing for use in brewing. Also the elements from craftbrewer are nice smooth, easy to clean, stainless units - you will be able to clean them off with a quick wipe with a rag, no twists, bends etc to worry about. While the bigger units are normally water heater elements and are generally a bit more convoluted.

Me personally - I wouldn't build a system with these sorts of elements at all - I would do this

http://www.aussiehomebrewer.com/forum/inde...mp;#entry741566

Or some variation thereabouts, with a bog standard 2400W over the side element to add a little grunt to the situation when heating your strike water or trying to get to the boil. You only have a 50L pot, so i am assuming you are planning on single BIAB batches. Those crown elements are proven to hold a sufficient boil for single batches, so no need for control of the element during the boil, no extra installation or wiring for a "second" element & those elements seem almost perfect for installation under a false bottom. You also, by building a system like that, happen to be building a perfectly serviceable RIMS mash/lauter tun. So if you ever decide to to go 3V - all you do is take the bag out and add a kettle and HLT... No mods required for the mashtun/RIMS whatsoever.

There are bunch of different things that can and will work - just dont get too stuck in the BIAB paradigm for this build, its only partially applicable. Look at what you want, why you want it - and at what other people have done in similar situations. You really aren't doing anything new here, no need to re-invent the wheel.

TB