Yeast and Sugar

[brwmistr]

I did an experiment last Saturday using a different brewing water that my normal.
I used maple sap in place of my tap water.
Using 7.6 liters I found that the natural pH of the sap was at 6.0. I next added my Millet grain crushed very fine (course flour) I held the mash at 50C for 25mins then added to my mash tun and the raised the temp to 65C for one hour. Once all this was boiled and the hops added I had 14Liters of 1.022 wort. I pitched 7g of coopers ale yeast at 22C and after 4days the ferment is done and sitting at 1.002.

So during this I was watching the volcano of action. I know that yeast metabolize the yeast and this makes heat and so the inside temp can reach higher temps but my temp stripe only raised to 24C yet the Beer tastes like bananas. I know this to be a "off" flavor due to temps the yeast raised to and Yes I know how to control that but are there members here that are bio-engineers that could explain that yeast "dance" in the fermentor.

 

[passedpawn]

explain that yeast "dance" in the fermentor.

Yeast don't have any means of propulsion. That "dance" is the result of the evolving CO2 churning the water, which then carries yeast and protein material and everything else around the carboy.

 

[brwmistr]

ah just that simple. With this energy comes the heat rise in the wort I guess.
Thanks

 

[passedpawn]

ah just that simple. With this energy comes the heat rise in the wort I guess.
Thanks

Nope, the motion of the gas and wort is not causing that heat.

Cell respiration is quite complex, but described thoroughly in organic biology texts. There are several large cycles involved, during which molecules (glucose, alcohols, water, etc) are converted to other molecules, and the energy that had bound the atoms together is released.

About 30% of that energy is used to create ATP molecules, and the other 70% comes off as heat. That's what makes fermentation "exothermic", and why your fermentor does get warmer.

 

[brwmistr]

I get the "exothermic" reaction bit. Same thing that happens to my epoxy to make it harden up. Wonder how much heat the breweries use back from this type of heat source? Or if its even worth it. At the amount they brew it should be something back I would think.

 

[passedpawn]

I get the "exothermic" reaction bit. Same thing that happens to my epoxy to make it harden up. Wonder how much heat the breweries use back from this type of heat source? Or if its even worth it. At the amount they brew it should be something back I would think.

I think the big guys have glycol jackets on their tanks for maintaining fermentation temps. So they are hauling that heat off in glycol loop. It's likely that the heat is then removed in a chiller outdoors somewhere, on a roof or something. So I doubt the heat being generated is used at all. To bad if that's the case.

New Belgium in Colorado generates a large percentage of their power from a farm of solar cells. If anybody is attempting to harvest the heat generated during fermentation, it would probably be them.

 

[brwmistr]

Just a few words on the test batch.
I'm two days from bottling this batch and so far it looks and tastes awesome. SRM: 5 range IBU: 79
Will have spent 1 week in the fermenter on Saturday.
I started with 15.2 (4G) and boiled down to 13.5Liters to a Wort that was 1.024
I will post a picture of it in the Hydro tube soon. This was my 4hrs test run. So far I'm happy. We will see after 2weeks in the bottle.

 

[brwmistr]

Here is the Fermenter one week later.

Also the other Picture's are my homemade Millet malt I use. The only issue I have with my own malt is I need to be able to control the process better for repeatability.