# Bad Excelsior ?



## KRich Frogger (Feb 15, 2013)

So i keep having problems lately with my ff cultures they take off but then mold will start to form on the top of the media then it will cover the top and wipe out the ff's...no they are not kept in the dark or under a light or near sun light just on a rack in the room....i dont get it happens the worst with the Excelsior, but also happens with coffee filters too


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## Rusty_Shackleford (Sep 2, 2010)

What kind of media are you using?
Are you using straight water or are you mixing vinegar with the water?


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## KRich Frogger (Feb 15, 2013)

In the past it was josh frogs media, that went fine until the last 1/4 of the bag. Now i am using some from mike over at glass box tropics, I use boiled tap water....which like i said was never a problem in the past....but i guess i could try out bottled water


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## Splash&Dash (Oct 16, 2012)

KRich Frogger said:


> In the past it was josh frogs media, that went fine until the last 1/4 of the bag. Now i am using some from mike over at glass box tropics, I use boiled tap water....which like i said was never a problem in the past....but i guess i could try out bottled water


an easy way to test if this is the issue is make one without excelsior, either leaving a space void or using something like coffee filters.

But I don't think it would be impossible for excelsior to go bad, though I assume it's something you would likely notice before using it (it's not exactly sterile in the best of conditions)


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## Pumilo (Sep 4, 2010)

Excelsior is a natural, wood product. It is not sterilized. There is always a good chance of introducing mold spores. I like to prepare my cultures with media and excelsior, put the lid on, and microwave them to kill any mold spores. After they fully cool I spike them with a pinch of active yeast and some flies.


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## xIslanderx (Dec 8, 2012)

How long in the microwave?



Pumilo said:


> Excelsior is a natural, wood product. It is not sterilized. There is always a good chance of introducing mold spores. I like to prepare my cultures with media and excelsior, put the lid on, and microwave them to kill any mold spores. After they fully cool I spike them with a pinch of active yeast and some flies.


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## Dendrobati (Jul 27, 2012)

We had a period if time where we lost every culture week after week for four or five weeks before we resolved the issue. Prior to that, we never had any mold issues. 

I was already doing the yeast thing as well as cider vinegar, I had used both boiling water and room temp water. I even bought new media. Finally I found the issue....excelsior. 

I started storing the excelsior in the freezer and taking out to make cultures. In fact....I add the flies and then a few days later I add the excelsior. The results have been great. Our cultures have never been better. Mold isn't an issue. I'm loving fly cultures again!


Keep us posted! 

Brad


Sent from my XT901 using Tapatalk now Free


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## Reef_Haven (Jan 19, 2011)

It is possible you are transfering mold spores into new cultures with your flies. Dusting your flies with calcium and allowing them to clean themselves of the dust a time or two might help reduce the mold. The same technique is used to reduce mite transfer to new cultures.


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## WendySHall (Aug 31, 2010)

KRich Frogger said:


> ....i dont get it happens the worst with the Excelsior, but also happens with coffee filters too


I wouldn't think the problem is the excelsior if it's also happening with coffee filters. Have you tried making up your cultures and then nuking them in the microwave? I nuke four cultures at a time for four minutes and haven't had any mold issues.


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## clifford (Oct 17, 2008)

I had a horrible time with mold when I first got started with fly cultures...but I've totally eliminated the issues now.

Things I changed:

-I wash my hands and make the cultures on a freshly cleaned desk
-I use less media than I used to. 1/2 cup per quart canning jar. My old cultures would always burn out/get mites/stink prior to using most of the media. I also find it sticks in the jar better with less (so it doesn't start to come loose while tapping the jar for harvesting).
-I use a half-cup cheap white vinegar and then add water (usually less than a quarter cup) until the mix looks right
-microwave for a minute and a half on high for 4 cultures (not boiling, but too hot to pick up with bare hands).

I only make 4 new cultures a week, so I'm no expert, but I haven't had a single crash since making this change, and the jars are far easier to clean when they're nearly empty at the end of 6 weeks or so.


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## ecichlid (Dec 26, 2012)

clifford said:


> -I use a half-cup cheap white vinegar and then add water (usually less than a quarter cup) until the mix looks right


 Interesting. What's the theory behind the vinegar?


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## Rusty_Shackleford (Sep 2, 2010)

ecichlid said:


> Interesting. What's the theory behind the vinegar?


The vinegar helps to prevent mold. As does the active yeast. Cinnamon is also a natural mold inhibitor.


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## oddlot (Jun 28, 2010)

I used to use vinegar and cinnamon,but it stinks and I used to hear about it from the wife.Now I use Methyl Paraben and cinnamon with excelsior.I never have mold issues.I do use boiled water but I never nuke the cultures.I don't know how much the cinnamon actually helps,but either way it smells good 
Good luck with your future cultures.


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## Pumilo (Sep 4, 2010)

xIslanderx said:


> How long in the microwave?


Pretty much what Wendy does. I start with hot tap water to mix them. Then I microwave 4 or 5 cultures for 4 minutes.


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## Splash&Dash (Oct 16, 2012)

WendySHall said:


> I wouldn't think the problem is the excelsior if it's also happening with coffee filters. Have you tried making up your cultures and then nuking them in the microwave? I nuke four cultures at a time for four minutes and haven't had any mold issues.


totally missed the part about using coffee filters. But yes. If it's showing up in both instances, it's unlikely it's the excelsior (though it could have been the "original source" an endless number of other things could have been, as well). 

The first thing I would try is mixing your cultures on the dryer side, especially if it's a problem unique to the new media you're using. Also nuking them might help


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## bobrez (Sep 10, 2011)

Pumilo said:


> Pretty much what Wendy does. I start with hot tap water to mix them. Then I microwave 4 or 5 cultures for 4 minutes.


Thats much longer than I nuke it! I use mason jars so that matters, i would think most plastic would melt in 4 to 5 mins. I nuke 4 cx for 77 secs, for 5 cx's would just add few secs, like 83 secs. Depends on power of ur nuker, mine boils cup of water in 2min flat


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## Ed (Sep 19, 2004)

ecichlid said:


> Interesting. What's the theory behind the vinegar?


The idea is that the low pH prevents the mold from getting a hold in the culture... I have significant doubts about it's effectiveness as some molds that infest the cultures (Aspergillus niger for example) do just fine even in extremely low pH enviroments. In fact A. niger can out compete competitors by dropping the pH pretty far down.. 

See some of the discussion in this thread http://www.dendroboard.com/forum/food-feeding/85688-intimidated-ffs-5.html#post762944 

Some comments 

Ed


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## Ed (Sep 19, 2004)

KRich Frogger said:


> So i keep having problems lately with my ff cultures they take off but then mold will start to form on the top of the media then it will cover the top and wipe out the ff's...no they are not kept in the dark or under a light or near sun light just on a rack in the room....i dont get it happens the worst with the Excelsior, but also happens with coffee filters too


Is it fluffy or is it a whitish slimy mass? 

Some comments 

Ed


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## WendySHall (Aug 31, 2010)

bobrez said:


> Thats much longer than I nuke it! I use mason jars so that matters, i would think most plastic would melt in 4 to 5 mins. I nuke 4 cx for 77 secs, for 5 cx's would just add few secs, like 83 secs. Depends on power of ur nuker, mine boils cup of water in 2min flat


Yep, they're pretty darned hot when I take them out. They don't melt...but I have found that I have to leave the lids slightly askew during the nuke or the sides of the culture will suck in. Mine also will boil water within two minutes (1000 watts).

Also, I wasn't using my head when I posted or I would've also mentioned that I utilize methyl paraben as well as cinnamon in my fruit fly media. Here's my recipe which is a pretty common one...
6 c potato flakes
1 c brewer's yeast
1 c powdered sugar
2 T cinnamon
1 t methyl paraben


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## Ed (Sep 19, 2004)

WendySHall said:


> Yep, they're pretty darned hot when I take them out. They don't melt...


The standard culture containers are made to be autoclaved so they can handle some heat.... 

Some comments 

Ed


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## frogparty (Dec 27, 2007)

You could quit using it altogether and instead use a reusable plastic mesh. Problem solved


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## Ed (Sep 19, 2004)

frogparty said:


> You could quit using it altogether and instead use a reusable plastic mesh. Problem solved


If that is the actual source of contamination and not say the tools used to collect the flies.... 

Some comments 

Ed


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## Splash&Dash (Oct 16, 2012)

bobrez said:


> Thats much longer than I nuke it! I use mason jars so that matters, i would think most plastic would melt in 4 to 5 mins. I nuke 4 cx for 77 secs, for 5 cx's would just add few secs, like 83 secs. Depends on power of ur nuker, mine boils cup of water in 2min flat


yeah, I always nuked in the 45s-1m range.


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