MBT - Revision history

Orfy at 17:32, 14 November 2007

2007-11-14T17:32:40Z

Mrkristofo at 03:02, 8 October 2007

2007-10-08T03:02:20Z

Mrkristofo at 02:57, 8 October 2007

2007-10-08T02:57:46Z

Chapka at 02:44, 24 September 2007

2007-09-24T02:44:17Z

Chapka at 13:39, 16 September 2007

2007-09-16T13:39:16Z

Chapka: New page

2007-09-14T01:23:14Z

New page

Chapka: New page: FORCETOC Category:Beer Category:Beer chemistry Category:Troubleshooting Category:Flavor problems Category:Aroma problems '''MBT''' is the abbreviation for '''3-met...

2007-09-14T01:01:52Z

New page: __FORCETOC__ Category:Beer Category:Beer chemistry Category:Troubleshooting Category:Flavor problems Category:Aroma problems '''MBT''' is the abbreviation for '''3-met...

New page

__FORCETOC__
[[Category:Beer]]
[[Category:Beer chemistry]]
[[Category:Troubleshooting]]
[[Category:Flavor problems]]
[[Category:Aroma problems]]

'''MBT''' is the abbreviation for '''3-methyl-2-butene-1-thiol''', a compound formed by the reaction of [[isomerized alpha acids]], specifically [[isohumulone]], with riboflavin in the presence of certain wavelengths of [[light]]. MBT is very similar in chemical composition and odor to the spray of a '''skunk'''.

==Causes of MBT==

MBT is created when [[wort]] or [[beer]] containing [[isomerized alpha acids]], which are extracted from [[hops]] by boiling and contribute [[bitterness]] to beer, is exposed to certain wavelengths of ultraviolet and blue visible [[light]]. In the presence of light, one iso-alpha acid, [[isohumulone]], reacts with the riboflavin present in wort or beer to form MBT.

Because the reaction is specific to hop acids, [[me

==Preventing MBT==

MBT can be prevented by avoiding exposing [[wort]] or [[beer]] to the relevant wavelengths of [[light]] after the completion of the boil. Sunlight skunks beer faster than other kinds of light, and fluorescent light is also a problem; incandescent light contains less of the relevant wavelengths of light. Beer stored in clear, blue, or green carboys or bottles should never be exposed to sunlight or fluorescent light, and exposure to incandescent light should be limited. Beer should be bottled in brown bottles wherever possible to minimize skunking, but even brown bottles should not be left in sunlight for long periods of time. In clear or green glass, skunking can happen in a matter of minutes.

Some commercial breweries that bottle their beer in green or clear bottles avoid skunking by using special hop extracts which do not contain [[isohumulone]], thus eliminating the problem of skunking altogether. This is not practical or desirable for most homebrewers.

@@ Line 7: / Line 7: @@
 '''MBT''' is the abbreviation for '''3-methyl-2-butene-1-thiol''', a compound formed by the reaction of [[isomerized alpha acids]], specifically [[isohumulone]], with riboflavin in the presence of certain wavelengths of '''light'''.  MBT is very similar in chemical composition and odor to the spray of a '''skunk'''.
+[[Image:MBT.gif|thumb|MBT]]
-−
 [[Image:MBT.gif]]
-−
 ==MBT in Beer==

← Older revision		Revision as of 02:57, 8 October 2007
Line 7:		Line 7:

	'''MBT''' is the abbreviation for '''3-methyl-2-butene-1-thiol''', a compound formed by the reaction of [[isomerized alpha acids]], specifically [[isohumulone]], with riboflavin in the presence of certain wavelengths of '''light'''. MBT is very similar in chemical composition and odor to the spray of a '''skunk'''.		'''MBT''' is the abbreviation for '''3-methyl-2-butene-1-thiol''', a compound formed by the reaction of [[isomerized alpha acids]], specifically [[isohumulone]], with riboflavin in the presence of certain wavelengths of '''light'''. MBT is very similar in chemical composition and odor to the spray of a '''skunk'''.
		+
		+
		+	[[Image:MBT.gif]]

	==MBT in Beer==		==MBT in Beer==

@@ Line 6: / Line 6: @@
 [[Category:Aroma problems]]
-'''MBT''' is the abbreviation for '''3-methyl-2-butene-1-thiol''', a compound formed by the reaction of [[isomerized alpha acids]], specifically [[isohumulone]], with riboflavin in the presence of certain wavelengths of [[light]].  MBT is very similar in chemical composition and odor to the spray of a '''skunk'''.
+'''MBT''' is the abbreviation for '''3-methyl-2-butene-1-thiol''', a compound formed by the reaction of [[isomerized alpha acids]], specifically [[isohumulone]], with riboflavin in the presence of certain wavelengths of '''light'''.  MBT is very similar in chemical composition and odor to the spray of a '''skunk'''.
 ==MBT in Beer==
@@ Line 14: / Line 14: @@
 ==Causes of MBT==
-MBT is created when [[wort]] or [[beer]] containing [[isomerized alpha acids]], which are extracted from [[hops]] by boiling and contribute [[bitterness]] to beer, is exposed to certain wavelengths of ultraviolet and blue visible [[light]].  In the presence of light, one iso-alpha acid, [[isohumulone]], reacts with the riboflavin present in wort or beer to form MBT.
+MBT is created when [[wort]] or [[beer]] containing [[isomerized alpha acids]], which are extracted from [[hops]] by boiling and contribute [[bitterness]] to beer, is exposed to certain wavelengths of ultraviolet and blue visible light.  In the presence of light, one iso-alpha acid, [[isohumulone]], reacts with the riboflavin present in wort or beer to form MBT.
-Because the reaction is specific to hop acids, [[mead]], [[wine]], and other [[fermented beverages]] that do not contain [[hops]] may be safely exposed to [[light]].
+Because the reaction is specific to hop acids, [[mead]], [[wine]], and other [[fermented beverages]] that do not contain [[hops]] may be safely exposed to light.
 ==Preventing MBT==
-MBT can be prevented by avoiding exposing [[wort]] or [[beer]] to the relevant wavelengths of [[light]] after the completion of the boil.  Sunlight skunks beer faster than other kinds of light, and fluorescent light is also a problem; incandescent light contains less of the relevant wavelengths of light.  Beer stored in clear, blue, or green carboys or bottles should never be exposed to sunlight or fluorescent light, and exposure to incandescent light should be limited.  Beer should be bottled in brown bottles wherever possible to minimize skunking, but even brown bottles should not be left in sunlight for long periods of time.  In clear or green glass, skunking can happen in a matter of minutes.
+MBT can be prevented by avoiding exposing [[wort]] or [[beer]] to the relevant wavelengths of light after the completion of the boil.  Sunlight skunks beer faster than other kinds of light, and fluorescent light is also a problem; incandescent light contains less of the relevant wavelengths of light.  Beer stored in clear, blue, or green carboys or bottles should never be exposed to sunlight or fluorescent light, and exposure to incandescent light should be limited.  Beer should be bottled in brown bottles wherever possible to minimize skunking, but even brown bottles should not be left in sunlight for long periods of time.  In clear or green glass, skunking can happen in a matter of minutes.
 Some commercial breweries that bottle their beer in green or clear bottles avoid skunking by using special hop extracts which do not contain [[isohumulone]], thus eliminating the problem of skunking altogether.  This is not practical or desirable for most homebrewers.

← Older revision		Revision as of 13:39, 16 September 2007
Line 7:		Line 7:

	'''MBT''' is the abbreviation for '''3-methyl-2-butene-1-thiol''', a compound formed by the reaction of [[isomerized alpha acids]], specifically [[isohumulone]], with riboflavin in the presence of certain wavelengths of [[light]]. MBT is very similar in chemical composition and odor to the spray of a '''skunk'''.		'''MBT''' is the abbreviation for '''3-methyl-2-butene-1-thiol''', a compound formed by the reaction of [[isomerized alpha acids]], specifically [[isohumulone]], with riboflavin in the presence of certain wavelengths of [[light]]. MBT is very similar in chemical composition and odor to the spray of a '''skunk'''.
		+
		+	==MBT in Beer==
		+
		+	MBT is not generally considered appropriate in any beer style. However, some brands of lager, notably Heineken, are packaged in such a way that the creation of some amounts of MBT (and therefore skunk flavor and aroma) is almost inevitable. Many beer drinkers, especially in the United States, have come to associate this character with the beer itself and consider it part of the beer's character.

	==Causes of MBT==		==Causes of MBT==