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pH of Depc H2O - Does anyone know? (Oct/04/2005 )

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So, homebrew, are you saying that Pyramid puts some DEPC into their apricot ale???



"This, by the way and completely off topic, is also a problem in brewing beer, unless you like fruity beers..."

As far as I'm concerned Homebrew, beer and science are always ON topic biggrin.gif


There are several esters that are important in brewing: isoamyl acetate (a banana flavor), ethyl acetate (imparts a concentration dependant flavor -- from flowery to solvent-like -- as concentration increases), and ethyl caproate (often described as imparting a wine like and fruity taste) are some examples.

Some of these esters are actually desirable, depending on what type of beer you're brewing -- a good Hefeweizen should have some banana flavor, such flavors in a lighter beer (like an Alt) would be terrible mistakes...


QUOTE (HomeBrew @ Oct 11 2005, 05:47 PM)
QUOTE (John Buckels @ Oct 11 2005, 12:07 PM)
I don't trust the stuff. I've autoclaved it overnight and still seen inhibition of RT reactions. The smell never goes away

Here's what Ambion says about the smell remaining after autoclaving:

3. Autoclaving DEPC-containing solutions should be of sufficient duration to rid the solution of any smell.

FALSE. A faint EtOH smell may linger after autoclaving, but more commonly a sweet, fruity smell is observed. This is caused by the EtOH by-product combining with trace carboxylic acid contaminates and forming volatile esters. It does not mean that trace DEPC remains in the solution.

This, by the way and completely off topic, is also a problem in brewing beer, unless you like fruity beers...

More here...

i always worried about that smell and really never trusted my prep of depc H2o because of it. thanks so much for the info. no one in my lab except me works on RNA so they could'nt explain it either. The stuff on the beer is even more fascinating! biggrin.gif biggrin.gif


I checked the pH of some DEPC water from a commercial company, since I was having trouble eluting DNA from gel purification columns with it. The pH turned out to be around 4. DEPC water made in the lab or from a different company may have a different value. When in doubt, check the pH of your reagents.

QUOTE (coco @ Oct 4 2005, 01:03 AM)

does anyone happen to know what is the pH of Depc H2O? I know it is a little bit acidic, but how much?



Iam trying to make DEPC treated water....juz help me down with the correct protocol...
i have got two protocols....
1. Add 0.1ml DEPC to 100ml of the solution to be treated and shake vigorously to bring the DEPC into solution.
Let the sloution incubate for 12hours at 37°c.
Autoclave for 15minutes to remove any trace of DEPC.

The second protocol.....goes...
Add 1ml of 0.1% DEPC to 1000ml distilled water
Mix well and let set at room temp for 1hr
Let cool to room temperature prior to use.

Now i have a brought a DEPC (5ml) from SIGMA juz tell me the concentration of DEPC in the first protocol is higher while in the second it is lower...geneerally what do you all do....???i need the info fast.....



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