Very long flocc time

[mikekchar]

Last week I made my first rennet cheese at home (although I've made others with my dad at his place).  The recipe uses MA4001 but only allows 15 minutes ripening time.  It took quite a long time to get a clean break and I proceeded even though it was a bit sloppy.  I'm making the same recipe today but made a few changes.  First, I added the culture at 27 C and then raised the temp over 12 minutes to 32 C.  At that point I waited 15 minutes and continued as normal (adding CaCl, waiting 5 min then adding the rennet).  One major change I did was dissolving the CaCl and rennet in cold milk on the theory that my dechorinated water may not have been dechlorinated.  This time I measure the flocc time: 35 minutes!  It was pretty obvious, too.  One minute it looks just like milk, the next, when I put my temperature probe in, I could see that it was starting to congeal.

Last time when I made my cheese it turned out very well.  I had no problems with curds shattering and my yield was very good.  The cheese was delicious.  So there is no problem per se.  I'm just a bit curious if others think that this flocc time is strange.  I'm just about to cut the curds for this cheese now and things seem to be going just as before.  No real differences at all.  My only thought is that my milk might be really strongly buffered and it's just taking a really long time to acidify.  Unfortunately I don't have a pH meter :-(

Any thoughts?

[mikekchar]

Again replying to my own post.  I was rereading Mastering Artisan Cheesemaking to see if I could get some clues and I noticed that she mentions that excess calcium chloride can *slow* rennet set.  Interestingly, I used more CaCl2 the second time than the first and the flocc time was slower the second time.  So, I maybe there is sufficient calcium in my milk already (it's vat pasteurised at 63 C)  Next make (which I hope is Wednesday) I'll cut the CaCl2 to maybe a quarter and see how it goes.

Edit: Just thinking this through a bit and more likely is that the CaCl2 I have is at a higher concentration than Caldwell has.   CaCl2 has a solubility of 64g per 100ml at 10C.  Unfortunately the label doesn't say anything about the strength :-(  However, when I put some in brine I was making, the brine became slightly bitter, so this is probably what the problem is.

Edit 2:  Yep.  That's it.  Went to the vendor site and they say the concentration is 50%.

[ArnaudForestier]

Hey Mike -

Are you using DVI or some sort of bulk or mother starter?  I used to have extremely long drops in pH due to using dry culture, and had to play with that because I make alpine cheeses exclusively, and with tommes, I had to manage a slow acid curve while trying to keep floc times reasonable (I use a multplier, not a clean break method). 

I can't find more than a few logs as it's been many years away for me, but I seem to recall some at times ridiculous periods to any pH drop and as well, floc times - easily well over an hour or more.  I just tried to tweak the culture for change in pH (also, it can be almost nothing, as they are replicating, then a really quick drop as they go to work), and to get the floc time to within a 12-15 min. window.

Are you certain of the freshness of your rennet?  Using cold water?  Sprinkling it in quickly once you've diluted it?

Just saw your edit on the CaCl concentration.  I'm used to around 30-33%.  Unfortunately I think linuxboy, Francois, not sure on Sailor aren't around any longer as they were my science gurus but I don't know why free calcium would have an inverse effect like that on floc time (I have her book, though, and am going to see).  Interesting.

Anyway, the short thought is to make sure you're getting acid production, make sure you're using fresh rennet, diluted in cold water (I used to put my beaker of dilution water in the freezer, while doing other things), and adding the rennet as quickly as possible.

Hope this was helpful.  Sorry for the length.

[mikekchar]

Thanks for the thoughts! :-)  Yest, I'm using a DVI culture.  I'm not really sure of anything yet because both the culture and rennet were purchased recently.  Caldwell has an interesting flocc test in her book where you task 60 ml of milk and 1.2 m of rennet (of single strength rennet -- I have double strength, so it should be 0.6 ml).  The idea is that you should get flocculation in less than 20 seconds.  If you don't, then you add calcium chloride to some new milk and try again.  This should help me determine what's causing the problem.  If I get good flocc times with just the milk, then I don't need calcium chloride.  If not and I get good flocc times with the calcium chloride, I'll try a new make with the correct amount of calcium chloride.  If that doesn't work, then it's probably the pH (or some other unknown factor).  If I can't get good flocc times with either, then it's the rennet.  Perhaps it is not double strength as advertised.  I'll try doubling it up.  I think somewhere in those possibilities I should be able to figure it out :-).

I'm going to give it a try tomorrow if I can squeak it in with work.  At the very least, if I can't figure it out, it isn't a disaster as I seem to be making good cheese anyway...

[mikekchar]

OK.  Very interesting results and I think it points in a direction that makes sense (at least to me).  First, I'll describe the experiment because I didn't have the details correct previously.

Ingredients:

• 6 drops double strength rennet (0.3 ml)
• 10 ml cool water (with a drop of milk in it to counteract the chlorine present)
• 30 ml milk at 33 C (in practice I ended up with 30 C)
• 0, 1, or 3 drops of Calcium Chloride (CaCl2)

I heated the milk in the microwave in earthenware sake cups.  Note: My microwave heated the milk from top down, so the top can get to  40 C while the bottom is still at 22 C.  It took me a while to get the hang of it.  In the end, I went with 6 seconds and it worked out well.  I transferred the milk to a brandy glass.  I put 6 drops of double strength rennet in the water (in a sake cup), swirled it around end then dumped it into the brandy glass.  (At that point the temp of the milk had fallen to 30C).  I then swirled the glass watching for it to flocculate (it is very obvious -- you get lots of white specs coming out of solution).  I timed how long that took.

With no CaCl2, it took more than 2 minutes to flocc (i.e. I gave up).  Next I tried again, putting 1 drop of CaCl in the brandy glass before adding the milk and then swirling it around.  It took 1 minute 38 seconds to flocculate.  Next I tried again, putting 3 drops of CaCl in the brandy glass.  It took 12 seconds to flocculate.

This tells me that my milk is very calcium deficient and I need to add more CaCl.  I'm going to *try* to do a make on Wednesday (if I can get milk -- I bought the last litre the store had today).  I will write here again to report any progress (if there is some).

[awakephd]

Very interesting. First hand tests are always helpful, as milk can vary so much from place to place. I haven't  done any testing in a long time, simply because I have procedures that seem to work pretty consistently with the milk I can get - and the milk is "standardized" store bought, so doesn't vary much.

[ArnaudForestier]

Yep, agreed, Andy.  MIke, I think it's awesome you're following through on your testing like this.  I appreciate your approach and would love to hear more as you continue. 

[mikekchar]

Sorry for the late followup!  I couldn't get any more milk and work became busy, so I wasn't able to do anything.  However, I had 800ml of milk left from my flocc tests, so I decided to make up a *very* small batch today.  I scaled down my original recipe by 4 (from 4 litres) and doubled the calcium chloride.  This means that I have about +20% rennet and double the calcium chloride.  The culture... um... I tried my best to scale it, but I put in 2 skewer tips which I think is probably the most imprecise measure ever :-)

I'm currently waiting for the rennet to set and things are promising.  I didn't quite recognise the flocc.  Whereas before I could see some gelling around where I moved my temperature probe, this time it just kind of coated the probe at around 15 minutes (possibly a minute or two before).  Since the milk is kind of old, I thought it was cream.  But at about 25 minutes  it was gelled enough to cut.  Just now I checked it (40 minutes) and it's a pretty clean break.  I figure the flocc time was pretty close to 15 minutes, so I'll leave it until 52 minutes (3.5 x flocc = total time).

So general success!  I'm making cheese curds out of this (too small to press, even for me!)  I'll post later today for general taste.  I'm a bit worried about possible bitterness from the calcium chloride.  We'll see.

Edit: All done!  They taste great.  I little bit low in acid.  I should have let them ripen a bit longer after cheddaring (and I only cheddared for 45 min as well).  First time I've done cheese curds.  No problem with bitterness that I can detect.  I've dry salted them and I'll try them in a day or so.  On another note, I got strangely high yield again.  112g of cheese from 803g of milk.  That gives me a 12.4% yield.  However, I cut the curds *very* small (too small, really) and added a 45 minute cheddaring.  No pressing, though, which might account for it.  Still, I think this gives me some confidence to say that the protein/fat content of the batch I had is a bit higher than what they published.

[mikekchar]

New update.  The above conclusions were WRONG 

It just didn't sit well with me that the milk could be *that* low in calcium.  It seems like I was needing more calcium than would be there in the first place.  What could be going wrong.  And then it hit me.  I was using the same measuring spoon for the calcium chloride as the rennet and I was either rinsing it with tap water or not rinsing it at all (not sure which).  I think whatever remained in the teaspoon played havoc on my rennet.  I decided to try my normal method again using reasonable levels of calcium chloride and -- voila!  Normal floc times (somewhere between 10 and fifteen minutes -- I didn't pay close attention).  Clean break at 45 minutes as expected.

Mystery solved (it's usually something simple :-P)

[awakephd]

Ah, the eternal problem of uncontrolled variables. I have a bad habit of trying to make half a dozen changes all at once, and then I can't tell which one(s) actually made any difference!

[mikekchar]

Sigh... Clearly something environmental...  Today I'm 29 minutes and counting... :-P

Edit: Flocc achieved at 31 minutes (using floating cup test this time, but verified with my "dipping the probe in the milk" method to see that it's basically the same).  This time the only thing I can think is that the rennet sat in the water for about 1-2 minutes before I added it to the milk.  I'm thinking it's got to be something about that.  Perhaps my attempts at dechlorination aren't working, or there is some residue in the cups from something...

[awakephd]

Mike, it does sound like there may be something interfering with the rennet, and the water or such is a good place to start. Can you get distilled water? Also, what regimen do you use to sanitize your equipment - could there be some residue there, as well as / instead of the cup?

I've read somewhere that a few drops of milk added to the water before adding the rennet can ensure the chlorine is de-activated - that's a very fuzzy memory, so not sure I trust it. Maybe someone else can verify or dispute ...

[mikekchar]

I have heard that as well.  I use iodophor for cleaning my plastic equipment and boiling for the metal equipment.  Crucially the cups and measuring spoons get the iodophor treatment (with rinsing).  I'm guessing that it's something to do with residual iodine or chlorine from the rinse water.  I boil and cool tap water for dilution and add a few drops of milk.  Sodium metabisulphate will also dechlorinate water (and I have some), but I'm worried that it might also interfere with the rennet.  I'll try to find distilled water, but the problem is that I don't know what it's called in Japanese.  :-)  My cheese is turning out well, so I can't really complain -- it's lucky that the cheese I want to make is tolerant of the long set times.  It would be nice to fix this, though...

[awakephd]

Ah, sounds like you're on to something. I confess that I just boil/steam the plastic equipment as well as the metal - but I boil any cheesecloths that I will be using at the same time, and make sure they are on the bottom, so that they are less likely to melt by being in direct contact. Measurement with a thermometer indicates that with a couple of inches of water in the bottom at a good boil, and a lid or other mechanism to hold the steam in, the temperature in the steam is well above what is needed for sterilizing. At least, it has worked for me for about 110 cheeses made now ...

[mikekchar]

That is a brilliant idea!  Thank you :-)  I'm going to give that a try.