# Chevre Problem- needs trouble shooting



## Aja-Sammati

I have just had a second batch of chev turn out bitter! Once I can accept as a fluke, but twice is way too much for me :sniffle Any ideas? I have never had this problem before. Milk tastes fine, too, no feed changes. Milk is pasteurized before culturing. I use veal rennet and a MM from dairyconnection. Both are fresh.


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## Rose

What kind of pan are you using? 

What are you draining it in?


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## Aja-Sammati

Stainless steel, sterilized before each batch is begun/ cheesecloth, sterilized before each batch is begun.


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## NubianSoaps.com

dairyscience.info and PAV to explain the science speak on there  The longer the girls are in lactation the less rennet I use, and it definetly effects bitterness if it's coming from acid. And a change in culture as the season progresses. There are cultures that make cheese more acidic/bitter, and those that don't...and salt...bitterness can not form in a cheese with enough salt in it (course this was a hard cheese problem for me, so perhaps this doesn't count with cherve).


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## buckrun

I also dropped my rennet levels in later lactation.
Yes thanks to Pav we may all learn how to do this!


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## linuxboy

OK, so here's what happens. Chymosin (aka rennin) is a special kind of enzyme that selectively cleaves certain parts of the proteins found in milk. Timewise, it cleaves the 105-106 bond (Phe-Met) of k-casein first out in the open, and then goes after others in ninja stealth mode. What does that mean and do? Well, k-casein is the casein that lets milk caseins to have a charge, and in this way to remain in suspension in water. When you take the charge away (by rennin splitting the k-casein), it coagulates the milk.

This would be all cool if all rennin did was cleave k-casein and then took a nap. But, it's like a terrier. It then goes after other fractions of the casein micelle. One of those fractions is beta-casein. Beta casein has a very strongly bitter terminal (by terminal I mean a peptide, a part of a protein) as part of its structure, and rennin cleaves that terminal. When that happens, the bitter peptide is liberated and causes a bitter sort of sensation. What makes it taste bitter is that it cannot be in water (trying to find a simple way of saying this), it is hydrophobic. I don't recall the exact threshold, but to the tongue, it is not that many PPB.

Late lactation milk is really special. For one, the total amount of caseins increase. For another, the makeup of the casein fractions change. And for a third, the level of fat increase is not as high as the protein relative to summer milk.

This means for late lactation milk for making chevre:

- Cut your rennet amount. Cut it way down, by 50% or even more, depends on your milk composition
- Treat it gently unless you correct the PF balance. With the higher proteins and lower fat, it will drain faster.
- Drain cold if possible. With the extra proteins and balance of a to b to k caseins, it's more prone to bitterness
- Try adding rennet later in the make, when the pH is 5.9-6.0. This will mean you can use less rennet and get the same set because rennet is more active at lower pH.
- Drain for less time. The curd sets up faster because of the higher solids
- Increase the culture amount, or again, add rennet later per above pH target. More solids means more of the acidity is buffered. If the rennet is in contact for a long time before proper acidity builds up to drain, it can be problematic.

Vicki is also right, culture selection makes a difference re: bitterness (strains have varying amounts of peptidase and protease activity). But that's more for aged cheeses. For fresh cheese, culture selection is more about developing flavor and mouthfeel (MM100 vs FD vs 4001, etc). If it's bitterness in chevre, it's caused by a protein breaking down and releasing a hydrophobic peptide through enzymatic action. That enzyme can be rennet, or come from some other similar source. How much are you using?


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## Aja-Sammati

Pav- most of this makes perfect sense to me except for a couple of things. 1) My late lactation milk is usually the same in protein, but up to 3% points higher in bf. 2) My curds are taking longer to frain than normal, not shorter. Do these things change the problem at all? Also, the batches were fine to taste when I took them down, but went bitter within 5 days, which makes sense to me now with the rennet still being active. I have a smaller batch hanging right now that I did less than 1/2 of the rennet on- I cultured for about 1 1/2 hours, then added the rennet. It took about 14 hours to get firm enough to ladle the curds, as opposed to 10-12.


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## linuxboy

Interesting. I based the assumption from published studies and the behavior of winter milk for me. YMMV  Maybe I was thinking of a different breed or misremembering.

With higher butterfat, it's also different. The curd is more fragile, and drains slower, as you said.

One thing I didn't mention is that the moisture content also accelerates the breaking down of protein. Maybe with the slower draining it's staying more moist for too long?

Are you draining at room temp? If you drain for a while at room temp, that makes for more active rennet action than draining in the fridge.

This might be as simple as that -- high butterfat, slower draining, excess rennet, and protein breakdown that happens too quickly.

14 hours is an OK time to set. If you want it to set a little faster, add rennet after 2-3 hours, when the acidity is higher.

How much rennet did you use for the latest batch?


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## linuxboy

Just thought of something else - might be the higher levels of plasmin that usually accompany late lactation milk. And possibly in combination with the higher fraction of y-casein. Hard to tell without diagnosing on multiple fronts. But adding less rennet and adding rennet later and draining cold should help. Late lactation milk is also usually higher pH. Mine has been creeping up into the 6.6s lately


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## Island Creek Farm

I'm curious here...my Chevre sets up enough to cut/ladle within two hours...max. It's always set up fast, and we are 8 months fresh, but it's been that way all through summer. Longer than that, it turns into jello and the chevre ends up bitter. Think I need to invest in a ph meter...??? So far it's turning out GREAT...like cream cheese, may not be how it's "supposed" to be, but we love it! Am I actually making something other type cheese?

Also, Hoegger's Chevre, I believe it's FD..can anyone confirm? Anne at Hoeggers was less than helpful last time I called, so I'm not jumping at the phone to find out!


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## linuxboy

Amanda, that's rather fast to set up. I've never used that culture; does it have rennet? Mine sets up in 6-8 hours usually. How much culture are you adding?

And hey, if you like it, I say keep doing it


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## Aja-Sammati

When I was using single use culture packs from New England Cheesemaking, I didn't have any problems with any of my cheeses...BUT someday I want to own a creamery, and will be workingon bulk cultures, so I might as well practice now!


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## nightskyfarm

I use M100 from dairyconnection.com with 3 drops of single strength veal rennet for 3.5 gallons. Of culture, I use 1/8 tsp+- and add rennet shortly after the culture. I allow it to sit for 12 - 14 hours and then drain the curd for about 8 - 10 hrs or until the desired cosistency is reached. I have cut back on the rennet of late from 4 to the 3 drops. No problems with chevre and all my does are late lactation at this point.


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