Gianaclis Caldwell  @  ChelseaGreen

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All ‘Bout Bloomies- Secrets of Making White Mold Ripened Beauties

Posted on Monday, September 19th, 2011 at 8:14 pm by Gianaclis Caldwell

When you talk about French cheeses most of us immediately think of Brie and Camembert. These two surface ripened cheeses are easy to love and are, arguably, the most imitated cheeses in the world. They seem to represent sophistication of palate and are therefore the gateway cheese to a whole new world of taste.  Camembert and Brie, however, are just the edge-of-the-wedge (that’s my cheesy metaphor for tip of the iceberg). There are an almost uncountable number of surface ripened cheeses- and yes, most of them are French!

In order to make delectable bloomy rind cheeses you must either get lucky or you need to understand the special needs of a cheese that has the most complex ripening pattern of any made. To begin gaining this understanding, lets take a simplified look at the lifecycle of your typical, everyday bloomy rinded cheese and then I’ll talk about just what is going on that ensures the results you want. And then, the always pertinent, common problems.

The Bloomy Lifecycle- Simplified

  1. Curd is produced either through a lactic (acid) production over a day or two, or through a quick-set, rennet coagulation.  This curd is not cooked or heated. Usually it is made with aroma producing and acidifying mesophillic cultures and the addition of white molds- penicillium camemberti (same thing as p. candidium) and often geotrichum candidium. Sometimes yeasts are added too.
  2. Molding is done when the correct pH is attained and is either by pre-draining of the curd in a bag for a couple of hours and then ladling (this is really helpful when making pyramid shaped cheeses and logs such as Pouligny Saint Pierre and Saint Maure), ladling thin slices of curd into the forms, or ladling rennet curds into large forms (such as the big guys they use to make Brie).
  3. Draining occurs without pressing and over 12-24 hours. Pyramids are not turned, but most other shapes are.
  4. Salting occurs after the forms are unmolded.
  5. Drying occurs over a 1-2 day period. Room temperature is usually about 62F and the humidity 80-85%. Turning takes place a couple of times during drying.
  6. Ripening is done at 50-55 F and 95 % humidity until a good coverage of white molds exist. Turning takes place daily during this time.
  7. Holding occurs if the cheese needs more ripening. The desired temperature is lower, about 38 F, to slow mold growth and allow for softening of the paste. Often the cheeses are wrapped to prevent drying out and to keep the mold from growing more. But if the humidity can be maintained at 95 F, then the mold can be patted down instead. If not wrapped, the cheeses should be turned.
  8. Eating occurs when you want it too! Some bloomies are best firm, others soft. Start trying them young and decide for yourself.

Understanding the Special Needs of Bloomy Rinds

1.  When the curd is put in the molds the pH of lactic curd is quite low, about 4.5.  Because rennet curd has a lot of whey at molding, it goes into the forms at about 6.4 and will continue to drop in pH during draining to reach the goal of about 4.7.

Digging Deeper:  Low pH means that the cheese has a low buffering capacity due to the loss of calcium in the whey. (Low buffering means the pH is easy to change which is critical to the development of texture later). Low pH (high acid) also means that plenty of lactate will be present (you’ll see why that matters in a sec!)

2.  The right amount of salt (usually 1-2% of the weight of the drained curd) is critical to limit undesired molds and encourage the more salt tolerant white molds. It is also important for flavor.

3. The surface of the cheeses must be dried after salting. Most molds don’t like a really wet environment (they like humidity, which is different than actual moisture you can see), but undesirable molds like mucor (aka cats fur) does like it wetter.

4. The white molds and yeasts eat the lactic acid and lactate, and start to grow on the surface (the molds need oxygen, so a good air exchange in the ripening area is critical).

Digging Deeper: The rate at which lactate is moved from the core to the surface depends on the permeability of the curd. Some things that effect permeability are:      Humidity- If the right amount of moisture must be presents. Fat content- High fat will impede permeability.

5. The surface microflora produce ammonia which is high in pH (basic) and it starts to increase the pH of the cheese.

Digging Deeper: Ammonia diffuses toward the core of the cheese over it’s ripening if the curd is permeable.

6. As the pH rises, the milk proteins attract more water and soften. (another reason for the high humidity!)

Digging Deeper: The farther proteins move from their isoelectric point (at which they have no charge) the more they attract water (become hydrophilic). As they bind water, they soften and become more creamy (at above 6.0 pH).  This softening of the milk proteins is called resolubilisation.

7. The breakdown of proteins and fats by molds and yeasts will help with the softening of the texture, but it is no longer believed to be the main reason for the texture change.

There, piece of cake, right? You totally get it? No, just keep making cheeses and return to this information, it will fall into place one day, I promise! (Hey, it did for me)Here are some common problems encountered when making bloomies. Most of the solutions are simply the opposite of the problem, but that’s true with most things in life…

Common Problems and Solutions

Not enough white mold growth: Surface of cheese is too moist, not enough oxygen (or too much carbon dioxide in air, too much geotrichum growth.

Solutions: Next time, dry the cheeses better; ensure airflow: spray on additional p. candidium (camemberti).

Too Firm Texture: pH not low enough at draining. Fat content too high. Too low of humidity. Too low oxygen.

Solutions: Track pH during make, lower fat content, monitor humidity, increase air exchange.

Too Runny: Presence of too much geotrichum or other highly proteolytic microorganism (especially when runniness is at the surface only), too low pH (less than 4.5) during draining, too high ripening temperature.

Solutions: Don’t add geotrichum, heat treat or pasteurize milk to remove wild strains, monitor pH better, lower ripening temperature once mold growth is established.

Toad Skin:  Too much geotricum, too high ripening temperature.

Solutions: Be sure to add about 100x less geotrichum than penicillium, lower ripening temperature and make sure salt levels are exact (g. candidium doesn’t like salt).

Mucor (Cat-Hair) growth: Too much moisture, too high pH.

Solutions: Choose mucor resistant penicillium strain, monitor pH at draining, ensure that drying phase is at 60-64 F and 80-85 % relative humidity.

Bitterness: Breakdown of proteins to bitter peptides by p. camemberti or other enzymes such as from rennet.

Solutions: Encourage things that promote even ripening so that the white mold doesn’t breakdown the outer portion of the cheese too quickly. Use geotrichum to balance the proteolysis of penicillium. Use the right amount of culture and the right variety (with less proteolytic activity.

Even though these cheeses might seem too persnickety to be able to work with, there is still room for error in the process with a happy outcome. (Much like many relationships…) Just give it a try, document your process, and if you like the resulting cheese, there you go!  Do remember, that because the pH goes up in these cheeses (from the safe, pathogen-unfriendly level of 4.7) that they can easily grow some nasty bacteria. This is why our ever-concerned FDA worries about soft-ripened cheeses. And you should too! Become educated about food safety and know if the milk you are working with is bacteriologically safe. Or pasteurize it.

Gianaclis Caldwell is the author of The Farmstead Creamery Advisor.

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