autolysation controller on the cheap

[mogur]

Nice thread on your heating/cooling controller, Bushman. I didn't even see it until I started posting this one. If you don't mind, I will go ahead with this thread anyway, though, since I'm coming from a cheap and quick point of view. (And I have a lot of somewhat fuzzy photos that I want to show off. )

This project was intended to simply control a crock pot at about 125F for autolysing yeast. I saw a cheap Chinese controller for $16 with free shipping. Usually only take 2-3 weeks, but this time I had to wait almost 7 weeks. Oh well, here it is, finally-

I didn't want wires hanging everywhere, so went down to the local hardware store and scored an outlet, a switch, a two gang plastic nail-on outlet box, a plastic cover plate, and an el cheapo two wire extension cord for less than 5 bucks.

Saber sawed off the nail-on wings, and on the smooth side of the outlet box, I marked a 2 9/16 inch by 1 inch rectangle. Drilling two holes in opposite corners made it easy to start the saber saw cuts.

Can't really tell that I used to be a carpenter, but it doesn't matter...

That's what a file is for

Sorry about the blur, but my hands were still shaking from the saber saw. Anyway, the hole needs to be 2 3/4 inches by 1 1/16 inches, so file away until the controller slips into the opening. This box was too small to allow for the retaining clips that come with the controller, so I stopped filing when the unit was a snug fit. Glue gun it at the end of the project if it is too loose.

Now the hard part is over and the fun begins.

[mogur]

If you are planning on plugging in any grounded appliance, or have exposed metal such as the outlet box or face plate, you must use a three wire power cord and ground everything in the box, especially the duplex outlet.

Otherwise, you can use a two wire power cord. If you want to skip the switch, here's is the simplest circuit-

I know that I won't be plugging in any grounded appliances, but I do like the switch for convenience, so here is my controller wired and ready for assembly.

Et viola!

And hard at work...

Unlike Bushman's, this controller is a single stage controller (either heating or cooling), but not both at the same time. It also uses an electro-mechanical relay, which you can hear click on or off. You can easily replace the relay with a solid state switch, which I didn't choose to do this time, because the controller has adjustable hysteresis, as well as adjustable time delay, and for autolysation, there is about a twenty minute duty cycle which will not push the life cycle ratings of the relay. I will show how to swap out the relay in a following post.

[mogur]

If you choose to use a solid state switch, the relay should be desoldered. It is the black box in the upper right corner of this drawing.

There are four pins that must be heated with your soldering iron at the same time. Just keep gently pulling on the relay while you go from pin to pin with the soldering iron, until all four are molten at the same time. It will release, just be patient and go around and around, shortening the time on each pin and the relay will start to pull away. Keep up the soldering iron action, however, until the relay is completely free.

Now use short pieces of solid copper wire to jumper from the input traces of the relay to the output traces. This will allow you to connect an external hockey puck relay to the controller using the screw terminals.

Now you can simply wire it like so-

NOTE: I edited this wiring diagram to correct an error in polarity of the SS switch.

[junkyard dawg]

Excellent post!

[mogur]

thank you, my friend

[Buccaneer Bob]

For those of you unsure what yeast "autolysation" or "autolyzation" (alternate spellings) is, you can check out mogur's awesome scientific comparison of a wide variety of yeast nutrients in the Sugar section.

I have done a lot of researching into yeast nutrients, myself, and I'm fairly certain mogur's study is the best one available anywhere in the public domain.

So anyway, autolyzation of yeast involves harnessing yeast's internal enzymes to break down the whole yeast cells into their most basic building blocks, which makes them about 100% usable as nutrients for another batch of yeast.

Another variation of this process is called hydrolyzation, which is pretty much the exact same thing, except that you use external enzymes -- usually from fruits like papaya, pineapple, fig, kiwi, etc. -- rather than the yeast's internal enzymes.

Both processes work best if the temperature of the yeast-and-enzyme slurry can be held in an "optimum" temperature range for around 24 hours.

Mogur's study of yeast nutrients, which focused on nutrient sources that are generally available in most grocery stores, indicates that autolyzed/hydrolyzed yeast is about the best yeast nutrient there is.

That said, this temperature controller that mogur has documented so well in this thread also has many other applications for the homebrewer/distiller including controlling heating elements, heating pads, submersible heaters, etc., used with mash tuns, fermentation tanks, etc.