Pasteurizing Raw Milk - Pros/Cons

[SANDQ]

Hi there can anyone help me? I make a stirred curd variety of goats milk cheddar using my own milk. The last 2 batches I have made I am getting alot less curd for the same amount of milk and the same process. Not throught choice I have chenged my brand of rennet, is this likely to affect the ammount of curd I am getting?    thanks  Q

[MrsKK]

Sorry, I really don't know about the rennet.  How far into their lactations are your goats?  I know that milk changes as an animal is farther along in lactation, and it can affect cheese yields.

[MarkShelton]

No, not in itself. The quantity of curd is determined by the quantity and quality of the milk. However, using different rennets may cause changes in the curd volume if the rennet varies in quality.
For example, if you switch to a lower quality or lower strength rennet, and you use the same amount as a previous rennet that was higher in quality/strength you may not get the curd firm enough for a clean break in the same amount of time. Then cutting the curd before it's really ready might cause the curd to lose more milkfat, reducing the yield.
If you switched to a comparable type of rennet, then I would look at the milk. I don't own any animals, so I'm nearly useless for advice in yield or quality of your own herd, but I do know that milking at different times of the year, or season, or day, or breeding cycle, has an affect on milk quality/quantity.
Can some milkers comment on this?

[edit] Looks like Karen beat me to the punch.

[FarmerJd]

I agree with Karen, as I have seen major fluctuations in my curd production at times, but I tend to agree with mark in your case because it obviously changed with your rennet. A good solution might be to use the flocculation method for determining cutting time so that your rennet quality can be compensated for somewhat. Do a search for "spinning bowl" method or flocculation to get details. Good Luck.

[mtncheesemaker]

Hi Karen and JD;
I have been noticing a smaller yield in my cheeses lately, and wondered about the lactation stages of the cows where I buy my milk. Can you increase the yield by using more rennet or CaCl (which I don't use), or, is it just something you live with?
Thanks,
Pam

[FarmerJd]

Pam, I don't think you can increase curd yield with rennet adjustment but you can maximize it by making sure you cut at the right time. (If I am wrong here I am hoping someone will correct) As far as CaCl, I am under the impression that it is used primarily for processed milk not raw. When your cows are not producing a large amount of solids in the milk, you just have to live with it unless you can control their diet. I hope that helps.

[Sailor Con Queso]

I had to switch from raw Jersey to Holstein a few weeks ago. My yield went down and my curd set was much weaker. I started adding a little CaCl2 and both yield and set improved. It may have improved anyway, but I'm going to keep adding it until my Jersey supplier is back online.

You can always add some cream back in to increase your yield.

I am beginning to understand why some traditional European cheesemakers don't make cheese during the Winter.

[mtncheesemaker]

Thanks, Sailor.  I did some reading in "American Farmstead Cheese" this afternoon. He says that a little CaCl will help with yield and curd firmness during these lactation periods that have low free calcium in the milk. I think I'm going to experiment with a minimal addition, 0.01% to the milk. I don't like to add anything to my milk besides starter and rennet, but think I will give this a try.
I made Camembert last week, added a quart of cream to 2 gal of jersey milk, and still had about a 25% reduction in normal yield. Plus, it took forever for floc/curd set.
At least now I know I'm not losing my mind (yet).
JD, do you think it is feed (hay here as we have a long winter) or lactation stage related, or both?
Thanks.
Pam

[SANDQ]

Can i ask,  I pateurise my milk, to a fashion I heat to 82 C sterilization point. Would using raw milk affect yield?

[FarmerJd]

Pam, thanks for the info about cacl addition. I am learning too. As far as whether it is feed or lactation stage,  it is probably both. There is no question that the lactation stage plays a part, but for my cows it is really not that noticeable. I also feed a very high quality feed in winter to compensate for lack of grazing. I usually adjust  the feed based on the milk quality. If it starts getting low in solids or cream I adjust my feed and it usually helps. I was having yield issues last fall and just replaced a whole batch of feed. The difference was almost instant. Sailor brought up the Holstein vs. jersey issue and there is no doubt about this being a factor.


SandQ, My understanding is  that raw milk usually gives a better yield, (I have never used anything but raw milk though so I could be wrong). I do not pasteurize though so I am uncertain what the impact of pasteurization on yield would be.

[Alex]

Can i ask,  I pateurise my milk, to a fashion I heat to 82 C sterilization point. Would using raw milk affect yield?

Don't pasteurize so high, 72 C for 15 sec (it's the time you turn off heat source and move your vat to cool) and add CaCl to compensate the loss due to pasteurization.

[linuxboy]

Oh! I didn't realize you weren't using raw milk. Just sort of assumed. If you pasteurize that high, it denatures proteins. Alex, 72 C for 15 seconds is still too high of a temp for cheesemaking. Use 63 C for 30 minutes. It is more gentle and will give you a better cheese. 72C for 15 secs is used for a continuous pasteurizer that pumps milk into a heat exchanger and rapidly heats the milk. Makes sense there because it stays in the heated loop of pipes for 15 secs, but doesn't make sense for a batch process like we use with cheesemaking.

Many professional cheesemakers who make raw milk cheeses do not pasteurize, but they will heat up to ~58-60 C to kill off some of the naturally ocurring bacteria so they can make more consistent cheese. You can try this approach as well, but age cheeses at least 60 days at at least 10 C.

[SANDQ]

Sorry I did not inform you I dont use raw milk for cheese.
As we sell our products privately and having worked on cow farms for years in Uk and Israel its been drummed into me the risks of raw milk for human consumption.
I will continue to sterilize my milk that I sell as milk. But, If you are saying that raw milk makes better cheese, I am prepared to go down that route. I am producing the cheddar with a view to sell it ( I have people queing up ) what are the health risks involved in using raw milk in cheese production?

[linuxboy]

Yes, it is true, that even if you handle raw milk exceptionally well, you have no idea what happens to it after it leaves the farm. And in such a case, other people's mistakes can result in tragedy. Cows are also different. If a cow decides to give you a "present" in the milk parlour, you just hose it down and keep going. There's e.coli often in the poop, and when you spray, it may go into the air, or land on the udder... and it's difficult to clean an udder completely. Goats are smaller and neater. I think it's easier to control quality with goats.

Cheese is different than raw milk. With cheese, the bacteria have a chance to die off if you age for several months at a temperature where the bacteria can suffocate. Also, with aged cheeses, you most of the time will know by smell or defects in the body (like holes) if the cheese is contaminated. Those two factors mean even if a cheese is mildly contaminated, it will not be dangerous. I can't even recall the last time an aged raw milk cheese led to any hospital cases. Milk, yes, fresh cheese, yes.

Many of the truly exceptional cheddars are made with raw milk, and some are made with pasteurized milk. I wouldn't say that by itself raw milk by default makes better cheese. I would say that all other things being equal, given two experienced cheesemakers and the same milk, it is more likely that a raw milk product will be more nuanced and complex because of the naturally occurring lactic bacteria there. It's the terroir of the cheese.

Even if you do pasteurize the milk, you don't need to sterilize or ultra pasteurize it. Heat it gently, to 145F for fresh cheeses, or even lower, to 130-135F for aged. Note the latter is not approved pasteurization temp. This will give you better curds. For drinking milk, do whatever you're comfortable with, and a case can be made for pasteurizing it for sales to limit liability.

If I would ever sell milk, I would do a hybrid approach. I wouldn't pasteurize with heat, but with UV, which is not approved as a legal method, so I would need to sell it as "raw", but UV treated, and attach all the usual warning labels. A UV treatment is much gentler, and still kills 98.8-99.999% of bacteria. Makes for better tasting milk, though, and many of the benefits of raw milk would be retained. I'd need to manufacture a UV milk pasteurizer... I don't like what's available today. Sorry for the aside.

[Alex]

Oh! I didn't realize you weren't using raw milk. Just sort of assumed. If you pasteurize that high, it denatures proteins. Alex, 72 C for 15 seconds is still too high of a temp for cheesemaking. Use 63 C for 30 minutes. It is more gentle and will give you a better cheese. 72C for 15 secs is used for a continuous pasteurizer that pumps milk into a heat exchanger and rapidly heats the milk. Makes sense there because it stays in the heated loop of pipes for 15 secs, but doesn't make sense for a batch process like we use with cheesemaking.

Many professional cheesemakers who make raw milk cheeses do not pasteurize, but they will heat up to ~58-60 C to kill off some of the naturally ocurring bacteria so they can make more consistent cheese. You can try this approach as well, but age cheeses at least 60 days at at least 10 C.

I am aware about what are you saying, but it's easier for me the 72 C than to hold 63 for 30 minutes. That's the way I pasteurize for years. I use only raw milk and do not pasteurize it for cheese I am going to age for 60 days and over.