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yeast

Posted: Sat Nov 05, 2005 11:40 am
by brewster14
what do they mean when they say "pitching the yeast at to high of a tempeture"...also i use prestige turbo 48 yeast...it says use 6 to 8 kg of sugar... is less better then more ??...will i have less nasties in my fermentation if i use less sugar ??...

Posted: Sat Nov 05, 2005 11:53 am
by linw
I'm struggling a bit with what is unclear about pitching at too high a temp. The yeast maker suggests the optimum wash temp for his product so just follow that. If the wash is too hot when you stir in the yeast/nutrients a lot of yeasties will die.

The answer to the second question is probably yes. A high sugar load will stress yeast more, resulting in more side products (other than etoh) being produced.

thanks

Posted: Sat Nov 05, 2005 11:59 am
by brewster14
thanks linw

Posted: Sat Nov 05, 2005 8:17 pm
by Uncle Remus
I posted on this before. I have found turbo yeasts are capable of producing very high % washes, but with the high av come a lot of nasties which require more work to clean up ie: running them 2 or 3 times, filtering with activated carbon. If you want to push turbo to it's limit, I've found its best do fast runs (I use a valved reflux still) with minimal reflux, maybe the distillate is 70% average. Save the product for 2 or 3 or 4 runs and then plug it all back in and use about use lots of reflux.

falling temp

Posted: Sun Nov 06, 2005 4:33 am
by brewster14
uncle remus, if my temp keeps moving up and down in the the middle of a run is that bad ?? the temp never goes above 78c but it tends to move up and down from about 65c to 78c...my hot plate has a thermostat on it and it keeps shutting the unit on and off....i purchased it from http://www.milehidistilling.com/" onclick="window.open(this.href);return false;" rel="nofollow they seem like great people and i dont think he would sell me a unit not suitable for the job...but anyway, falling temps is that a problem...i always thought the temp was suppose to be controlled thru the water flow...could you please help me a little on this subject

Posted: Sun Nov 06, 2005 8:01 am
by Uncle Remus
I don't think temperature fluctuation is really 'bad' but it must be take longer doing a run and having the distillate coming out in spurts. I use a propane burner so I've never experienced temp fluctuation problems.

Once my head temp reaches 78 deg C or 172deg F it remains constant until near the end when the av% starts dropping off then the head temp starts to climb and by that time I'm collecting tails.

The only thing I do with water is cut back the flow through the condensor coil to conserve water. I cut it back to a low flow, if I see vapour escaping from the top of the condensor chamber I increase the flow a little.

Like THM says try tweaking your hotplate so it doesn't cycle and gives you a constant heat.

Posted: Sun Nov 06, 2005 3:03 pm
by linw
The temp cycling is, indeed, bad. Very bad if you are trying to produce clean high abv product. (I'm assuming you have a reflux column).

Your column has to be stabilsed for good product. To do this we run at 100% reflux for at least 20 min at the start of each run. What you are seeing is the wash going off the boil. In theory, you should then re-stabilise your column with another 100% reflux session each time it does this!

I don't know how that plate could be sold for reflux (or any) still operation. But, somehow, you will have to stop it cycling on and off as others have said.

Good luck.