Subject: Mead Lover's Digest #1651, 3 November 2013 Date: Sun, 3 Nov 2013 19:33:06 -0700 (MST) From: mead-request@talisman.com Mead Lover's Digest #1651 3 November 2013 Mead Discussion Forum Contents: Re: Sterilizing question (Steve Piatz) Re: Sterilizing question (Paul Shouse) Re: Sterilizing question (Dick Dunn) NOTE: Digest appears whenever there is enough material to send one. Send ONLY articles for the digest to mead@talisman.com. Use mead-request@talisman.com for [un]subscribe and admin requests. Digest archives and FAQ are available at www.talisman.com/mead#Archives A searchable archive is at http://www.gotmead.com/mldarchives.html Digest Janitor: Dick Dunn ---------------------------------------------------------------------- Subject: Re: Sterilizing question From: Steve Piatz Date: Fri, 1 Nov 2013 14:43:42 -0500 Jack Eyton asked about light struck meads and sterilization. Regarding light struck meads, the process is the result of a chemical change in the mead as a result of exposure to high energy light, in particular exposure to ultraviolet light. In wines it results from riboflavin reacting with some amino acids to form hydrogen sulphide and mercaptans.. The important amino acids are cysteine and methionine. The resulting compounds can have the aroma/taste of leek, onion, cooked cabbage, wet wool and other unpleasant characteristics. In the wine world is seems that the amount of amino acids left in the wine makes a big difference in how susceptible the wine is to becoming light struck - aging on the lees will increase the amino acid content. In wines there can also be a precursor from the hydrogen disulphide which can degrade into mercaptans. The light stuck character is easier to notice in neutral white wines than red wines in part because there is less to hide behind. In addition, in red wine production there can be lower H2S content because of process differences. Sparkling meads that are bottle conditioned, therefore aged on the yeast, would be susceptible to becoming light struck more easily than the same mead that was force carbonated. In general, it seems there are many ingredient and process variables that would influence how susceptible a mead is to becoming light struck. The best way to prevent an infection is to maintain proper sanitation from the start through to packaging. I find Star San works very well for my meads. - -- Steve Piatz sjpiatz@gmail.com ------------------------------ Subject: Re: Sterilizing question From: Paul Shouse Date: Sat, 2 Nov 2013 08:19:23 +0900 >>This may be a dumb discussion but do meads get light struck in the same >>manner as white whines? I am wanting to know more about what exactly causes >>this to happen and if there is a way to prevent it. For example to pre treat >>to prevent light struck and then uv sterilize to clear an infection. As I understand it, mead, beer and wine can all be light struck but it has nothing to do with infection. The problem is a chemical change caused by exposure to light, especially UV light. This can cause a loss of aroma, color, and produce off tastes like cabbage, burnt rubber, etc. Exposing bottled mead to UV light would only make the problem much worse. The only way to prevent light strike is to keep your mead in a dark place during fermentation and aging. Keep it in a cellar or a closet, or cover the carboy with a blanket. Also, green or brown glass bottles can help limit exposure to light, that's why they are colored in the first place. I hope this helps. ------------------------------ Subject: Re: Sterilizing question From: Dick Dunn Date: Sun, 3 Nov 2013 19:29:30 -0700 In the last MLD, Jack Eyton asked about preventing mead from becoming light-struck. I re-read the post and decided that Jack isn't really dealing with a light-struck mead right now. Rather, he would like to do a UV treatment to deal with an infection, but doesn't want that to cause the mead to be light-struck instead, trading one problem for another. (Is that right, Jack?) If so, I've got two responses--neither of which address the light-struck question, sorry! First is: What sort of infection are you getting? In my experience, infected/contaminated mead is rare, mainly because it's just not very hospitable for spoilage organisms. So first try to prevent the problem from happening, instead of treating after it has started. Second is: Depending on the type of "infection", UV may not be very effective at stopping it. It might take an implausibly high level of irradiation to do the job. - -- Dick Dunn rcd@talisman.com Hygiene, Colorado USA ------------------------------ End of Mead Lover's Digest #1651 *******************************