Author Topic: Goat's Milk Yogurt Frustration  (Read 5858 times)

fjernsyn

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Goat's Milk Yogurt Frustration
« on: June 07, 2010, 03:17:29 PM »
Hi all!

I've been making our yogurt for about a year now, using organic whole milk from the grocery store, the ABY-2C culture from the Dairy Connection and my Excalibur Dehydrator set at 105 degrees as an incubator.

However, I now have access to raw, organic goat milk and so want to use that.

1st attempt: Followed directions on fiascofarm.com for raw milk yogurt (using the exact same culture, exact same incubator, etc. The only difference was that their milk was warm directly from the goat, while mine was cooled first. I warmed it to 105 degrees using directions on that site). The yogurt was basically just slightly thickened milk, and this from a culture that produces an almost-pudding-like consistency with cow's milk. 

2nd attempt: Realized I used as much culture as I normally did (1/16 tsp per 2 gallons) rather than the amount specified on the website. It made sense that my yogurt would have been really loose because of the natural bacteria in the goat's milk. Made again, using more culture. Thicker, but still very loose, stringy, not good.

3rd attempt: I did more reading on raw milk yogurt and, though frustrated because fiascofarm seemed to be able to get a thick curd using the exact same equipment where I couldn't, decided to give up and try cooking the milk first. Made yogurt the exact same way as I did with store-bought cow's milk. Not stringy, but not very thick. Definitely thicker than previously, but nowhere near even what I used to get using a store-bought yogurt as my starter, and the ABY-2C culture produces a much thicker curd than that. We did eat this batch.

4th attempt (yesterday): I brought the yogurt to 180 degrees as before, but left it there for 30 minutes. I also dissolved 2 ounces of gelatin into the yogurt when it was hot (for a 7 quart batch). This morning, after incubating yesterday and chilling overnight, the curd is what I would hope it to be (maybe slightly less thick than the cow's milk yogurt), but it's got a really weird taste. It's maybe slightly more sour than it generally is, but not much. It has a very long, strange aftertaste that is not pleasant. Any ideas? Could it be the gelatin? It's not a gelatin-y taste. I thought that by keeping it at 180 degrees it would kind of sterilize it, so it shouldn't affect the culture. I can't think of what else it would be though.

I'm so frustrated. Any help would be much appreciated!

linuxboy

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Re: Goat's Milk Yogurt Frustration
« Reply #1 on: June 07, 2010, 06:02:50 PM »
What's the off-taste? Goatyness? Can you describe it more? Your make details for the last batch seem right, so it's likely the milk or contamination.

mtncheesemaker

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Re: Goat's Milk Yogurt Frustration
« Reply #2 on: June 07, 2010, 06:24:20 PM »
I heat my milk up as you did but immediately cool it to 115F, then add the starter, usually 1T/quart of my last yoghurt batch. When making yoghurt with goat or sheep milk, I add 1/5 of a drop of rennet (1drop rennet mixed in 5T water, add 1T of this when I add the starter). This gives it a little body.
(All raw milk.)
Pam

fjernsyn

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Re: Goat's Milk Yogurt Frustration
« Reply #3 on: June 07, 2010, 09:15:48 PM »
linuxboy - There is a bit of a goaty taste, though not too bad. But the more unpleasant part is kind of a bubbly taste that lasts for a really long time on the tongue.

Pam - Interesting. How much milk per 1/5 drop rennet? 1 quart? I had heard you could do that, but also heard that that could lead to whey separation, whereas the gelatin keeps all of the liquid suspended. We like our yogurt really thick, and even with the cow's milk version of this, find that the second half of the jar is much less thick than the first because of some whey separation.

I suppose it could just be contamination of some sort, but I'm so frustrated that none of these batches have come out right, whereas all of my cow's milk batches came out perfect (once I decided to use freeze-dried culture every time - things were drifting too sour and too loose when I tried to use some of the previous batch's yogurt as a starter).

linuxboy

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Re: Goat's Milk Yogurt Frustration
« Reply #4 on: June 07, 2010, 09:51:40 PM »
Bubbles mean contamination because the fermentation pathway becomes not just lactic. I think you have some yeast or heterofermentive bacteria in there.

Goat's milk is hard in terms of yogurt making because it is whey proteins that help with strong coagulation, and they are way different for goat milk than for cow. Here's what the the best currently available science has to say for how to make a thick yogurt from goat's milk:

  • Increase strength of protein bonding by heating to 180-185 for 10-20 minutes. This denatures whey proteins (lactalbumen and lactoglobulin, see my discussion of this here: http://cheeseforum.org/forum/index.php/topic,2924.msg23880.html#msg23880 for more info), giving you a thicker set.
  • Use a stabilizing additive. Either a starch or gelatin work well. When using starch, pick one that doesn't interfere with mouthfeel, such as potato or tapicoa. Corn starch doesn't work well unless you cook the heck out of it.
  • Increase solids not fat percentage (SNF). To do this, you can boil away liquid from the milk, or microfilter the milk then standardize your BF, SNF, etc, or add powdered or evaporated milk.
  • Introduce enzyme to strengthen coagulum. Add a little bit of rennet, like you would for a chevre. This works best in combination with other methods. Of course, add enzymes at the right temp, meaning same time as you inoculate.
  • Drain to remove excess whey. Similar to a greek yogurt, you can remove extra liquid after it has coagulated
  • Choose a bacteria that has tendency to form polysaccharide bonds between the outer membranes of each other. This leads to long chains of bacteria that physically thicken the coagulum and help to retain water. A good example is leuconostoc and selective lactococcus species.


The above list incorporates two categories of approaches to solve to separate issues: whey separation and coagulum strength. One, you need to figure out how to prevent the liquid from separating from the coagulum. A starch helps with this, so does a stronger coagulum that retains water. Or you can drain to make a greek style. And two, you need to get the strongest coagulum possible. The tips above also help with that.

« Last Edit: June 07, 2010, 10:03:03 PM by linuxboy »

mtncheesemaker

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Re: Goat's Milk Yogurt Frustration
« Reply #5 on: June 07, 2010, 10:12:54 PM »
Sorry, I make a 2 quart batch and use 1 T for the batch.
Yes, you do get some whey separation. If you want it thicker, I would use LB's suggestion to just drain it a bit. I personally don't like to use additives.

fjernsyn

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Re: Goat's Milk Yogurt Frustration
« Reply #6 on: June 07, 2010, 11:59:56 PM »
Thanks for all of the tips! So I think I already tried 1, 2 and 6, so next time I'll do the same, plus #4. I don't want to boil down the milk as it's already a bit more caloric than whole milk cow yogurt, and I don't want to strain it both because of the previous reason and because I make so much at a time. Hopefully it's just a contamination issue (well, sort of - I sterilize everything and am really careful so I'm not sure what it would be). I am ordering a new batch of yogurt cultures today; maybe I'll find that the culture itself is contaminated?

Missy Greene

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Re: Goat's Milk Yogurt Frustration
« Reply #7 on: June 15, 2010, 01:03:37 AM »
Hi,
 I have been making goat milk yougurt for quite some time.  for  1 gal I heat to 185 for 30 min, cook to 115 add the same culture you are using then add rennet diluted 1 drop in 4T cool water, and  then add 1 T . cover with down vest. next morning I put the yogurt into my cheese muslin and drain it a bit.
 It is totally creamy and delicious. the pigs get the whey or sometimes I use it in baked goods. I also usually use 4 gal of milk at a time.
 Missy