Cheddar Swelling - Yeast Contamination

[DanW]

I've been working on small 1-lb batches of cheddar and my last two batches seem to start swelling about a month after I wax them.  When I took the first one out of the wax the surface was smooth, I cut it in half to see what was happening inside and the inside had a few cracks through the surface I cut.  The second one I cut (from a batch done two weeks after the first one, started swelling noticably about a month after waxing as well) had some cracks on the surface as well, but also smells fine.  I re-waxed them and put them back, hoping they're okay, but figured I'd ask and see if someone knows what's going on with them and whether they're safe to eat or not.  Planning on letting them age for close to a year to be on the safe side, but would prefer to know for sure. 
  The process/variables I had, I used whole milk from the store, calcium chloride, and both batches were cheddared and seemed perfect after pressing.  I dry them for around 5 days in the pantry, humidity around 25%, before I wax them.  They're aging in a wine cooler, temp 55 degrees, humidity around 65% (I haven't been able to get that better yet).  Any ideas and help would be greatly appreciated, since I'm new at this

[Cheese Head]

DanW, I have yet to have that problem, there is some info in the Wiki: Body Defects, Mechanical Holes article. As you used store bought milk I doubt it is Coliform or BAB infection, more probably a yeast infection, either airborn yeast or if making bread or beer at same time as made the cheese. Did it smell yeasty? Also, where are you in the world and do you trust your store bought milk source?

Also if you search on the whole forum on "swelling" you'll get a bunch of hits, ignore the posts in the Hard Cooked (Swiss) Board (as they often intentionally want holes and swelling), but you will find some good info in the other threads.

Also, a couple of snaps if you took them would help.

[DanW]

John (CH) thanks for the suggestions. When I cut open one of the cheeses to take some pictures I asked my wife (who has a more sensitive nose than I do) to see if she smelled anything, and she said it smelled yeasty to her. We tasted a little bit and thought it tasted good, but with a hint of bread flavor. I think I did make bread around the same time as the cheeses, so I'm guessing that's the problem, but I'm including the pictures just in case.
  What does it mean if it's contaminated with yeast?  Is it still okay to eat after aging it further, or will it keep swelling with time or go rancid after a certain amount of time?  It's funny, part of what I love about cheesemaking is using the whey to make bread within the next few days.  If I'm going to have my cheese drying in the kitchen pantry maybe I can't do that; I'll have to think of a way to avoid cross-contaminating the cheese with yeast.
 

[Cheese Head]

Hi Dan, wow, your presumably originally cylindrical cheese certainly did swell!

Here's a thread on concurrent cheese and bread making, and another thread here with similar picture to yours.

Yeast contamination is still OK to eat, just off flavors will develop.

On air drying after pressing in pantry where store bread, I think there is less of a chance then of yeast infection versus during the curd making phase.

[Sailor Con Queso]

Yeast fermentation and gas production kick in pretty quickly. So the timing suggests that it is a "Late Blowing"’ gas formation caused by Clostridium tyrobutyricum (normally after 4-6 weeks of ripening). One of the clues is the taste of butyric acid. What does the cheese taste like? I'll bet it's not yeasty or alcohol flavored.

[DanW]

I only realized the swelling was an issue when it popped the cheese wax seal around the edge, so odds are it was swelling for a while and the wax was moving with it while it could.  I probably should have realized when it started to "round" that something odd was going on, but... gradual changes and all that.  How long do I have before the off flavors would start developing?  It tasted great today, and I want to make sure to eat it while it's still good while letting it age as long as I safely can. 
  Sailor, out of curiosity, what is Clostridium Tyrobutyricum, and is it something that would be present in pasteurized milk or would it be an outside contaminant that can be found in a kitchen in the US?  What does butyric acid taste like?  The cheese tasted really creamy and smooth, and according to my wife slightly bready/yeasty. And can you really make alcohol-flavored cheese?
  Thanks for y'all's help on this, it's nice to know that my cheese isn't ruined, and more importantly for my peace of mind that I'm not making explosive cheese

[Sailor Con Queso]

Clostridium is a soil based contaminant that forms spores. The spores have to "hatch". That's why it takes a few weeks to show up.

Butyric acid is classified as a short-chain fatty acid. It has an unpleasant odor and acrid taste, but a somewhat sweet aftertaste (similar to ether). It is notably found in rancid butter, and vomit. Certain esters of butyric acid have a pleasant taste or smell, and are used commercially as additives in foods and perfumes. The low oxygen environment in the interior of a cheese produces the unpleasant varieties.

Based on your observations today, I would say this is not Clostridium.

[DanW]

  That's good to know, since it sounds much worse than yeast.  Any ideas on how long I can age the cheese before the yeast produces off flavors, or if the slightly bready taste is the off flavor and it won't get stronger than that?  Or possibly even how to fix it so the yeast stops inflating the cheese?

  -Dan

[Cheese Head]

Sorry, no clue, I'd say you're toast, enjoy what you've got (cheese on toast etc) and start again.

Ok that's a bit negative, you could try dehydrating the cheese further, that should reduce the swelling but frankly it's going to be a real uphill battle.

Good luck.

[Sailor Con Queso]

Cold compresses will reduce the swelling. 

[Boofer]

Cold compresses will reduce the swelling. 

That made me smile.

-Boofer-

[captaincurd]

My guess is that Sailor is correct.   If it's contaminated, it won't get any better.  I noticed the 55F temp.  IMHO that is a little warm to try to age a cheese for a year.  good luck

[DanW]

Well, thanks for all your help to all that replied, especially for the cold compress suggestion   My current plan is to eat the cheese I've made that's swelling, maybe keep a half-pound for "scientific experimentation" to see what happens when you age yeast-contaminated cheese for four months, since nobody seems to have done that before
  For the cheddar I was actually planning on 4-6 months aging, my wife doesn't like sharp cheddar.  I'm working on getting a better setup, but for now the wine cooler is the best I can do   One day, I'll have a real cheese cave...  Thanks again for the help, I'll let y'all know what happens to the yeasty cheddar in four months.

[Boofer]

I noticed the 55F temp.  IMHO that is a little warm to try to age a cheese for a year.

My cave hovers between 48-56F. So far everything seems to be doing just fine. Should I be cranking the Johnson controller lower? It's been at the same temp setting for a little over 18 months.

What would be your optimal temperature?

-Boofer-

[Sailor Con Queso]

I disagree Boof. I keep my cave at 54F and have cheeses in there that are over 2 years old.

Natural underground caves here in the USA average 54F to 56F year round. The famous Murray's which ages cheese underneath NY city keep their hard cheese cave at 53F and 83% RH. That fluctuates +/- 2 degrees.