Mold and the effective usage thereof in hard cheese (Parma Koji V1)

[Fates End]

Hey, I've been thinking about how to approach using koji (A. oryzae, a kind of white mold used traditionally to make soy sauce, sake, and miso) to create a hard cheese.

See, I'm a big fan of parmesan, but not that big a fan of waiting for things to age. I've never been the most patient person, and the idea of waiting over a year to crack open a cheese is not the most appealing thing in the world.
But recently, I've found, courtesy of the book Koji Alchemy, the idea of what it calls 'miso cheese'. As it turns out, the authors found that the enzymes produced by koji, when applied to cheese, produce the flavor of aged parmesan, but in a fraction of the time normally required.

The issue is, apparently the texture doesn't really change that much, and the only recipes they shared used bases of ricotta or an unidentified goat cheese - both generally soft, unpressed cheeses. There was mention of pressing ricotta to make something gratable, but I feel it just wouldn't be the same.
So it comes down to me to experiment. My idea is to start out following a standard parmesan recipe, but to deviate with aging. From how I see it, there's three possible options:

1. Shio koji in the milk or curds
Shio koji is a liquid extracted from koji killed with large amounts of salt. The enzymes are still active, but it's totally dead. The plus side here is that I wouldn't have to worry about penetration since the enzymes would be evenly distributed through the cheese from the start. On the downside, I assume that brining is done at the end instead of just adding salt to the milk for a reason. Shio koji, being what it is, is pretty salty.

2. Shio koji in the brine
This would be using shio koji as a base for the initial brine of the cheese. On the plus side, brines are supposed to penetrate through the whole cheese, or they wouldn't be all that effective. Also, no need to worry about the whims of a living thing. On the minus side, this wouldn't do all that much for the texture, and I'm not quite looking for something that cuts rather than crumbles.

3. Live koji rind
For this, I'd be treating the cheese as a surface ripened one; after brining and draining, I would treat the rind either with dried koji or koji spores, and make sure to keep the conditions good for the mold to grow couple months, before killing it off with a brine and brushing off the fuzz. Koji's good at absorbing moisture, and it would continually produce enzymes with no worry of running out of them. On the other hand, the rind would be less than ideal, but most importantly: I don't know if the mold on the outside would be able to alter the flavor at the center of a hard cheese. While there's plenty of instances of mold growing on hard cheese, you don't often hear about specifically hard cheese being surface ripened, and I've heard mention of mold not being able to penetrate hard cheese. I don't want to treat it like a blue either, since I've never heard of live koji making it into a finished food and don't feel like taking my chances.

What do you think? Which of these do you think would actually work? Could the enzymes from a surface mold reach the center of a cheese or would I be left with a layer of parmesan around a fairly unremarkable core?

[mikekchar]

I've only read one paper on the use of koji on cheese rinds.  Koji doesn't grow particularly well on cheese because the pH is not right (I forget what pH koji likes).  Indeed, I make miso at home and make natural rind cheeses and I've never had koji volunteer itself on my cheese.  I think you will be disappointed if you go the live route.  Brining with the enzymes *might* make a difference, but I admit that I'm skeptical.  The study I read said that they were unable to produce any interesting flavours with koji (one of the rare papers you see where it says, "We tried X and it didn't work").  I wish I had a link for you, but alas I'm terrible at that kind of thing :-(

Definitely give it a try, but I would temper expectations :-)  Cheese flavours are produced because enzymes (mostly) from the starter culture break down the proteins in the cheese into peptides and amino acids.  Proteins are long chains and different enzymes break the chains at different points.  Different enzymes at different tempteratures for different periods of times will produce different peptides and amino acids.  This is turn will produce different flavours.  It is highly unlikely that enzymes in koji will produce the same flavours as enzymes released from the breakdown of lactic acid bacteria cells.  For example, flavours produced by enzymes from penicillium candidum growing on the outside of brie cheese is responsible for that characteristic brie flavour.  You can't get that flavour anywhere else.  Finally, enzymes that break down protein quickly tend to do so by breaking down the proteins in large chunks.  There are two basic types of enzymes: those that take off "branches" of the proteins and those that chop up the "trunk" of the proteins.  The latter ones often work very quickly but they make large peptides that are bitter.  Over time the other enzymes can chop them up into smaller amino acids which is why young cheese can sometimes be bitter, but then get better.

As for Koji Alchemy, I believe that's the same book that states you can cover steak with koji and get the same effect of dry aged stake.  Tried it.  It does not work :-)  It's nice in its own way, but it's *nothing* like dry aged beef.  I think the authors have a lot of enthusiasm and a very low threshold for precision in their work, if I haven't mistaken the book.  YMMV, though.

[Fates End]

I've only read one paper on the use of koji on cheese rinds.  Koji doesn't grow particularly well on cheese because the pH is not right (I forget what pH koji likes).  Indeed, I make miso at home and make natural rind cheeses and I've never had koji volunteer itself on my cheese.  I think you will be disappointed if you go the live route.  Brining with the enzymes *might* make a difference, but I admit that I'm skeptical.  The study I read said that they were unable to produce any interesting flavours with koji (one of the rare papers you see where it says, "We tried X and it didn't work").  I wish I had a link for you, but alas I'm terrible at that kind of thing :-(

Definitely give it a try, but I would temper expectations :-)  Cheese flavours are produced because enzymes (mostly) from the starter culture break down the proteins in the cheese into peptides and amino acids.  Proteins are long chains and different enzymes break the chains at different points.  Different enzymes at different tempteratures for different periods of times will produce different peptides and amino acids.  This is turn will produce different flavours.  It is highly unlikely that enzymes in koji will produce the same flavours as enzymes released from the breakdown of lactic acid bacteria cells.  For example, flavours produced by enzymes from penicillium candidum growing on the outside of brie cheese is responsible for that characteristic brie flavour.  You can't get that flavour anywhere else.  Finally, enzymes that break down protein quickly tend to do so by breaking down the proteins in large chunks.  There are two basic types of enzymes: those that take off "branches" of the proteins and those that chop up the "trunk" of the proteins.  The latter ones often work very quickly but they make large peptides that are bitter.  Over time the other enzymes can chop them up into smaller amino acids which is why young cheese can sometimes be bitter, but then get better.

As for Koji Alchemy, I believe that's the same book that states you can cover steak with koji and get the same effect of dry aged stake.  Tried it.  It does not work :-)  It's nice in its own way, but it's *nothing* like dry aged beef.  I think the authors have a lot of enthusiasm and a very low threshold for precision in their work, if I haven't mistaken the book.  YMMV, though.

I think the pH tolerance might depend on varieties; apparently sojae koji tends to raise ph wherever it's used and black koji even creates its own citric acid, so those may work better than the standard yellow/white for colonizing cheese. For now though, I'm having difficulty finding sources for those varieties and it'd probably be best to get a baseline before experimenting with trying to grow different species.

And the protease notes are appreciated. Koji's particularly violent about protein breakdown so I'll be sure to wait at least the full two months recommended in the book before considering writing it off for bitterness.

As for the steak, I've heard good things about it. Similar flavor but more mushroomy, make absolute sure not to let it age too long. May be a matter of subjectivity.

And if nothing else works, I spose I can always out try the cheat method of seeding with MSG.

[Fates End]

Parma Koji V1 Trial, Pt. 1


Was going to make jack yesterday, but only one of my two gallons of milk were still good, so I figured I'd get going on my attempts at using a koji-accelerated parmesan. Mainly going off the NECMS recipe, with some cross-referencing to the curd-nerd recipe and some educated guesses based on Koji Alchemy.


First off, I used the powers of sorcery and having exactly the right amount of instant skim lying around to turn 1 gallon of whole milk into 2 gallons of 2% milk. I slowly heated it in my pot to about 140, and set a bowl of approximately this'll probably work dried koji and I guess this is enough blood temperature filtered water in a large covered bowl to soak.


After about an hour of sterilizing and soaking, stirring every 20 minutes, I added calcium chloride and switched off the burner. Once the milk was under 130 throughout, I added the excess soaking water and set the koji in a bag to steep like a fungal tea. 131 is the high end of the optimum temperature for koji's protease activity, so I wanted to take advantage of that before curdling. The lipases, meanwhile, won't really get going until room temperature.


At 110, I added in 3 cubes of thermophilic mother, cultivated from a vegan yogurt listing S. Thermophilus, L. Bulgaricus, L. Acidophilus, Bifidus, L. Lactis, and L. Plantarum and once they had melted set it on lowest heat on the small burner for about half an hour.


Once the pre-ripening was done, I fished out the koji, wrung it out, and added in a dissolved 3/4 of a tablet worth of my vegetable rennet and set my timer for 35 minutes.


While the cheese set, I mixed my steeped koji with the remainder of my 400g dry koji packet  in a gallon ziploc bag and added enough water that it was all noticeably wet.


Once the timer went off, I cut the curd into inch chunks with my cake knife, then, since they seemed fairly soft, I let it set for another 15 minutes, and cut it again a half inch offset, and let it sit for another 15 minutes. I did one last cut with my whisk, slowly and carefully going up and down, to get the curds into a... relatively even, though frayed, collection of chunks, and let it have one final 10 minute rest.


After that, most of the curd had sunk beneath the whey and a quick pH dip measured the acidity at around 5.5. I set the stove to gradually warm it., stirring occasionally with the whisk.


Once the temperature got back to 110, I raised the burner a notch and checked with a pH strip again; 5.0.


I reached 130 after raising the heat gradually and stirring more and more often, and finally, once the average temperature had it it, I quickly removed all the curd to a mold, which I then checked the drainage of before adding a can of tomatoes on top of to get the whey trickling.


I continued to add weight as the whey would slow down, until I ended up with a veritable Jenga tower of weight. I'd guesstimate the final pressing weight was somewhere around 50-80 lbs. Hopefully enough to consolidate the curd despite the acidity. I ended up shooting for 4 hours total, though I may have ended up short due to how late it was by that time. The pressed cheese was somewhat thin and floppy, but held together strongly enough that I didn't worry about breaking it when I flipped it. I'll certainly need to find a bigger pot if I ever want to make a respectably sized parmesan.


Weighing my wet koji, I got a total of 755 grams. Since I started with 400 grams, at most 355 grams of it is water. To get a slightly better hydration, I measured out 124 grams of pickling salt and added it to the koji, and washed it down with 118 grams more filtered water to reach a saturation of around 26%. After squishing it around in its bag for a while, I set it out at room temperature to digest. While standard shio koji takes around a week to be ready, I believe that's mostly just amylase reacting, and 'sweet' isn't really the flavor profile I'm looking for here. This should be ready to use as a brine base when the cheese is ready to brine in a few days (as per the NECMS recipe and the PR PDO standards).


The sheer amount of weight led to me not turning the cheese during pressing, which may be a mistake, but I did turn the cheese and remove the cheesecloth after I removed the weight for the night.


Oh, and because of how much acid whey I ended up with, I mixed in some baking soda and made it into ricotta. Low yield, but better than nothing.

[Fates End]

Now, time for the brining. But first, I found something great! Proof that koji can grow on cheese! Granted, I don't know the pH or the variety, just that it's a goat cheese made with 'a fairly standard process', but it's proof at least that koji can in fact form a rind.


Parma Koji V1 Trial, Pt. 2


Anyhow, after a few days of digestion, the koji is nice and soupy. I squeezed it through some cheesecloth and into a bowl, added two cups of water to make sure the cheese has room, and saturated the whole mix. Giving it the benefit of the doubt but erring on the side of caution, I'd say that this is about a quart total? Based on NECMS's brine formula, this would call for a quarter tablespoon of CaCl, which isn't exactly something I can accurately measure. So instead, I'll go for half a teaspoon and say that's good enough. No acid, since the cheese is already too acidic and the recipe doesn't call for that much vinegar anyway.


Now, everybody into the fridge! The cheese disc, having sat for one day unlidded in the mold and one day in a ziploc bag, I note, is cracked from poor handling and also because I underestimated how much the curd would shrink. All I can do for it now is to try to press it back together the best I can after it dries, patch up the cracks with shortening, and then bandage it when it starts to harden.


As everything chills and I make my coffee, let's do some math. The cheese is only about one pound and half an inch thick. At one hour per pound per inch, that means 1*1/2=1/2 hour? That doesn't exactly feel right, but it's more than the ratio in NECMS's recipe (four hours for a 2.5 lb cheese that looks more than 2 inches tall).


Seriously, did I really loose that much weight to whey?


When I took out the cheese to brine, it smelled notably yeasty. Geotricum? Well, any kind of yeast should die with a saturated brine, yes? Even with 15 minutes a side.


All in all, I'd say it's not as bad as it could have been? I mean, it could have fallen apart in the brine, while as it stands it's still in three pieces with one potential extra crack. I guess we'll have to see where this leads us. I really do need a bigger pot.

[Fates End]

Almost two weeks since the last post, I've liberally bandaged and larded the cheese with shortening, and have been keeping it in a ziploc bag in the fridge, flipping and opening the bag every day or two in order to keep the moisture up. My fridge is right about the perfect temperature, though this isn't the classiest solution.


The larding seemed to do fairly well keeping the cheese in one piece for the first week, but over the past few days it's failed, leaving only the bandaging itself keeping it relatively intact. I'm not sure if it's simple mechanical failure or if it's the enzymes from the koji doing extra duty degrading the shortening.

On the positive side, I haven't seen a trace of mold, mildew or bacteria on the outside of the cheese. I can still vaguely smell that sweet yeasty smell, but it's more than overwhelmed by the strong parmesan scent the cheese has already developed. Aside from the bready undertone, it smells exactly like storebought pre-shredded parmesan. I'm eager to see how good it turns out once the two months are up.