Author Topic: Slight cabbagey smell from the cheeses....Methanethiol?  (Read 2057 times)

Offline SalMac

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Slight cabbagey smell from the cheeses....Methanethiol?
« on: September 16, 2008, 05:07:55 PM »
Did some research and it appears it could be something called Methanethiol? Anyone know about this?

Most of the material I've read indicates its a natural byproduct but its a bit unnerving given the humidity problems I've had.

Sal


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Offline John (CH)

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Re: Slight cabbagey smell from the cheeses....Methanethiol?
« Reply #1 on: September 17, 2008, 10:25:46 AM »
No clue :-\, I like cabbage bit not in my cheese, so I'd say it's unwelcome . . . good luck!

Offline reg

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Re: Slight cabbagey smell from the cheeses....Methanethiol?
« Reply #2 on: September 18, 2008, 06:32:54 AM »
here is a little info that i found, hope it helps some.

Methanethiol
From Wikipedia, the free encyclopedia
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Methanethiol
 
 
IUPAC name Methanethiol
Other names methyl mercaptan
mercaptomethane
thiomethyl alcohol
Identifiers
CAS number [74-93-1]
SMILES  [show]
CS
Properties
Molecular formula CH4S
Molar mass 48.11 g·mol−1
Melting point -123 °C
 
Boiling point 5.95 °C
 
Acidity (pKa) ~10.4
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox references
Methanethiol (also known as methyl mercaptan) is a colorless gas with a smell like rotten cabbage. It is a natural substance found in the blood, brain, and other animal as well as plant tissues. It is disposed of through animal feces. It occurs naturally in certain foods, such as some nuts and cheese. It is also one of the main chemicals responsible for bad breath and the smell of flatus. The chemical formula for methanethiol is CH3SH; it is classified as a thiol.

Contents [hide]
1 Occurrence
2 Uses
3 St. Petersburg incident
4 Milan incident
5 Asparagus
6 See also
7 External links
8 References
 


[edit] Occurrence
Methanethiol is released from decaying organic matter in marshes and is present in the natural gas of certain regions, in coal tar, and in some crude oils.

In surface seawater, methanethiol is the primary breakdown product of the algal metabolite dimethylsulfoniopropionate (DMSP). Marine bacteria appear to obtain most of their protein sulfur by the breakdown of DMSP and incorporation of methanethiol, despite the fact that methanethiol is present in seawater at much lower concentrations than sulfate (~0.3 nM vs. 28 mM). Bacteria in oxic and anoxic environments can also convert methanethiol to dimethyl sulfide (DMS), although most DMS in surface seawater is produced by a separate pathway. Both DMS and methanethiol can be used by certain microbes as substrates for methanogenesis in some anoxic sediments.

Methanethiol is a weak acid, with a pKa of ~10.4. This acidic property makes it reactive with dissolved metals in aqueous solutions. The environmental chemistry of these interactions in seawater or fresh water environments such as lakes has yet to be fully investigated.

The United States material safety data sheet (MSDS) lists methanethiol as a colorless, flammable gas with an extremely strong and repulsive smell. At very high concentrations it is highly toxic and affects the central nervous system. Its penetrating odor provides warning at dangerous concentrations. An odor threshold of 0.002 ppm has been reported. The United States OSHA Permissible Exposure Limit is listed as 10 ppm.

reg

Offline SalMac

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Re: Slight cabbagey smell from the cheeses....Methanethiol?
« Reply #3 on: September 22, 2008, 11:50:27 AM »
Thanks for this Reg

I finally got worried enough to crack one of the worst offenders....aka the mongrel.

<sigh> Come clean Sal

The mongrel was a mix of all the curds that didn't fit in the mould over a ten day period that I kinda squdged together into the baby gouda mould and only pressed it with 10 lbs of weight. It was about 1 lb in weight and wetter than the others. It took forever to dry out and smelt cabbagey.

The identification that the cabbage smell was probably methanethiol came from this article :

http://www.teagasc.ie/research/reports/dairyproduction/4337/eopr-4337.htm

Key flavour compounds of Cheddar cheese
Identification of the key compounds responsible for Cheddar cheese flavour
Dr. Tom Beresford

The flavour of Cheddar cheese is influenced mainly by the choice of starter culture used. However, the rate of flavour development and ripening time are determined mainly by the ripening temperature.

I found this quite interesting and from this and other articles couldnt work out if it was a good or bad thing to smell cabbagey.

Sooo I decided to try it.

It was very good, very flavoursome, the texture, taste and rubberiness of a port salut?

I've rewaxed the remainder. Next time I try a bit I'll post a pic.

I am now quite interested in what determines flavour in a cheese.

Sal



Offline Tea

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Re: Slight cabbagey smell from the cheeses....Methanethiol?
« Reply #4 on: September 22, 2008, 03:15:00 PM »
Boy your game.  After seeing the colour of that cheese, I don't think I could have done that.   :o


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Offline SalMac

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Re: Slight cabbagey smell from the cheeses....Methanethiol?
« Reply #5 on: September 22, 2008, 03:43:53 PM »
Never posted a pic of this cheese Tea

Offline Tea

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Re: Slight cabbagey smell from the cheeses....Methanethiol?
« Reply #6 on: September 22, 2008, 04:01:23 PM »
Ooops my mistake.  When you said mongrel cheese, I thought you were refering to the other cheese you also called "mongrel" in another post.  You know, the one with all the colour mould growing on it.
Sorry.

Offline Baby Chee

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Re: Slight cabbagey smell from the cheeses....Methanethiol?
« Reply #7 on: September 25, 2009, 07:33:58 PM »
I found this quite interesting and from this and other articles couldnt work out if it was a good or bad thing to smell cabbagey.

Sooo I decided to try it.

It was very good, very flavoursome, the texture, taste and rubberiness of a port salut?

hahaha Oh yeah!  I'm glad I wandered by this thread.  My Stilton turned cabbagey.  I should have put it quickly into the proper 60ºF cave, but instead had the blue overtaken by something exotic and disgusting.  Hopefully this disaster will foster and interesting cheese in 7 weeks.


I'll be putting it in the cave to dry and cool as soon as my Cam. comes out.  I just don't want Mr. Funky here to cross contaminate.
“For centuries, people thought the moon was made of green cheese. Then the astronauts found that the moon is really a big hard rock. That's what happens to cheese when you leave it out.”

Offline Tropit

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Re: Slight cabbagey smell from the cheeses....Methanethiol?
« Reply #8 on: October 30, 2009, 09:33:03 AM »
Are you still alive this AM?  Please answer...I'm worried about you.   :o
~Cindy

Offline Baby Chee

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Re: Slight cabbagey smell from the cheeses....Methanethiol?
« Reply #9 on: October 30, 2009, 11:45:46 AM »
Haven't eaten it yet.

Those two are still sitting out back in the cave, drying up, getting tough, and ready for a taste in a few weeks.  They don't look very appetizing.  If I cut them open and they stink like a skunk, I'll have to toss them.
“For centuries, people thought the moon was made of green cheese. Then the astronauts found that the moon is really a big hard rock. That's what happens to cheese when you leave it out.”


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Offline DeejayDebi

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Re: Slight cabbagey smell from the cheeses....Methanethiol?
« Reply #10 on: October 30, 2009, 09:32:19 PM »
Gosh I couldn't even eat that Chee!

Offline Baby Chee

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Re: Slight cabbagey smell from the cheeses....Methanethiol?
« Reply #11 on: October 30, 2009, 10:01:08 PM »
^-^;  I was hoping it might subside into something interesting and edible.

It's not really subsiding.  The white kicked back up production recently and is getting very hairy indeed.
Not good.  Mold is now growing on mold which is growing on mold which is growing on curd....

Expect nothing good.
“For centuries, people thought the moon was made of green cheese. Then the astronauts found that the moon is really a big hard rock. That's what happens to cheese when you leave it out.”