Author Topic: Natural Rind - Black Fuzzy Mold Spots  (Read 4276 times)

Offline John (CH)

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Natural Rind - Black Fuzzy Mold Spots
« on: September 01, 2009, 07:16:56 PM »
Two of my currently 4 natural rinded cheeses have small fuzzy slightly raised black spots on part of their rind. It rubs off quite easily.

Attached picture is worst, my ~4 lb/1.8 kg whole cow's milk Gouda #5 at 17 days. I let the humidity get too high for a few days, and there they were :-[! Sorry about the poor focus with my camera.

My questions are: Is it a mold or something else, does it have a name, did I do something non-optimal to make it appear (like increased humidity), is it a concern, if more appear how should I remove, rub with salt water paper towel or vinegar etc?

Appreciate any advice . . . John.


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Offline Wayne Harris

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #1 on: September 01, 2009, 07:28:38 PM »
I am avoiding adding water my natural rind cheeses.  I have a brush exclusively for my cheeses that I have used to scrub the rinds of my cheeses.
I have heard of others using grain alcohol to sanitize the surface of the cheese.

I am coating my cheeses with a olive oil/salt mixture.
Wayne A. Harris - in vino veritas

Offline FRANCOIS

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #2 on: September 01, 2009, 07:43:29 PM »
It's blue.  Only salinity will kill blue, but be careful as it can cause problems for other microflora.  It all depends on what final rind you ar elooking for and what yo added to the milk/brine.

Offline DeejayDebi

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #3 on: September 01, 2009, 10:27:03 PM »
The blue ones need to be cleaned quickly if you wait a few days they grow roots. Maybe roots is not a good word but they will go "in" the cheese as fast as they grow on the cheese. Did that make any sense?

They kind of grow like a wort first on the surface then into the cheese.

Offline Alex

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #4 on: September 02, 2009, 03:02:02 AM »
Two of my currently 4 natural rinded cheeses have small fuzzy slightly raised black spots on part of their rind. It rubs off quite easily.

Attached picture is worst, my ~4 lb/1.8 kg whole cow's milk Gouda #5 at 17 days. I let the humidity get too high for a few days, and there they were :-[! Sorry about the poor focus with my camera.

My questions are: Is it a mold or something else, does it have a name, did I do something non-optimal to make it appear (like increased humidity), is it a concern, if more appear how should I remove, rub with salt water paper towel or vinegar etc?

Appreciate any advice . . . John.


Dip a piece of cloth in vinegar and then in some coarse salt. Use this combination as a file and clean the spots like you remove rust spots. Keep an eye for the next days, clean again if needed.
Alex-The Cheesepenter


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Offline John (CH)

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #5 on: September 02, 2009, 04:42:12 AM »
All, thank you for response.

Francoise, this was a straight forward Gouda, only Danisco's Choozit Mesophilic MM100 added as starter, no B linens etc. Sorry but I don't really know what type of natural rind I am looking for, just that I don;t want to go down the wax road.

When you say it is blue mold I assume you mean Penicillium Roqueforti. I haven't made any blue type cheeses for 7 months and when I used to make blue's they were bright blue - green almost turquoise and very flat-thin on surface. This mold is almost black and raised and almost hair like. Sorry but the camera colour of the mold isn't accurate.

When I rubbed it off it did seem to have roots and I needed to rub hard. Again appreciate support.

Offline FRANCOIS

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #6 on: September 02, 2009, 03:18:40 PM »
There are wild spores everywhere, even in our plant that runs 16/7/360.  Blue in particular is impossible to kill.  It was actually a joke at Danisco, people would ask what the shelf life of their blues were.  They'd tell people, shelf life wasn't an issue. 

Gouda is a very rich cheese for surface microflora.  If you want a clean, bare  rind...good luck.  It will be very labor intensive to keep it scrubbed clean.  The only way to do that is vacuum bag it.

Offline Zoey

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #7 on: September 03, 2009, 01:58:34 AM »

I'd love to work at a place where people make jokes about blue's shelf life.

That saved my day!

Offline Alex

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #8 on: September 03, 2009, 02:40:02 AM »
All, thank you for response.

Francoise, this was a straight forward Gouda, only Danisco's Choozit Mesophilic MM100 added as starter, no B linens etc. Sorry but I don't really know what type of natural rind I am looking for, just that I don;t want to go down the wax road.

When you say it is blue mold I assume you mean Penicillium Roqueforti. I haven't made any blue type cheeses for 7 months and when I used to make blue's they were bright blue - green almost turquoise and very flat-thin on surface. This mold is almost black and raised and almost hair like. Sorry but the camera colour of the mold isn't accurate.

When I rubbed it off it did seem to have roots and I needed to rub hard. Again appreciate support.


The description of the mold (black hair), leads me to the conclusion that what you have is "cat hair" mold. It is caused by insufficient draining of the curds and lack of salt. Clean it as I described in previous post.
Alex-The Cheesepenter

Offline FRANCOIS

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #9 on: September 03, 2009, 03:35:05 AM »
If that's mucor (cat hair) you have problems.  Mucor is incredibly sensitive to salt levels and usually only an issue on soft ripened cheese (like brie).  If you have cat hair on a gouda, your salt is way, way off.  We have some blue strains that do appear black and hairy, and are also somwwhat sensitive to salt, but it takes much more.  The cure, in either case, is a rub with coarse salt. 


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Offline Zoey

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #10 on: September 03, 2009, 05:30:52 AM »

I think it is great that John took this issue in discussion, and we've got some great advice from Francois and Alex (also the white mold thread).

I wonder if there is any resource in which there's more information on the different (unwanted) molds and the microflora issue mentioned by Francois. I'd love to read more about them, and I bet I'm not the only one.

Offline Alex

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #11 on: September 03, 2009, 10:34:29 AM »

I wonder if there is any resource in which there's more information on the different (unwanted) molds and the microflora issue mentioned by Francois. I'd love to read more about them, and I bet I'm not the only one.

Books, books, books ::)
Alex-The Cheesepenter

Offline Boofer

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #12 on: September 06, 2009, 01:00:55 AM »
I like Alex's corrective solution, salt & vinegar. I too developed a bad case of surface mold while trying to air dry some new swiss. The answers I found at the time were white vinegar or brine rubbed with a piece of cheesecloth. I think Alex improves on that.

The pics look like the color is deeper than just on the surface. Good luck.

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Offline FRANCOIS

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #13 on: September 06, 2009, 02:13:44 AM »
You really shouldn't just throw salt and vinegar at every rind.  It depends on what's growing there and what you want to grow.  You need to create an environment that allows what you want to grow but excludes those that you don't.  Rogue blues and blacks don't respond to vinegar but will to salt.  If, for example, you were trying to grow something with p. candidum on it and you swabbed with salt and vinegar, you'd kill off the p.candidum too.  In this case John is trying to keep the gouda surface clean.  He could use heavy brine, vinegar or grain alcohol with lots of scrubbing.  That will coer all bases since nothing will grow through that.

Offline John (CH)

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Re: Natural Rind - Black Fuzzy Mold Spots
« Reply #14 on: September 11, 2009, 02:53:57 PM »
OK, my washed rind cheeses are older, and brown-black spots are more pronounced. Pictures below are of my worst case by far, my Cheese Making #45 Havarti:
  • First picture is before I re-bathed the cheese in saturated brine to try and keep the mold at bay, some white which I assume Geotrichum candidum 13, many brown-black spots.
  • Second picture is close up after re-bathing.
  • Third is zoom in after re-bathing. Note some of spots have white centers, probably from where I had previously tried to rub them off with paper towel wet with brine.

Given better pictures, appreciate any updated diagnosis?

As you can see, I haven't been highly diligent about trying to rub these off, assume still safe to consume?