Yogurt Making - Erratic Consistency

[BigCheese]

Well, I am distraught. I cant seem to get consistent yogurt. How precise does the 185F for 30 min system need to be. Sometimes I need to go but I am only at like 175F, so I leave it an extra 10 minutes. There are various small variables like that.

It would be one thing if the consistency was alittle thicker sometimes, little thinner sometimes, but I get super thick yogurt in 7.5 hours sometimes, and yogurt that never really thickens, or has 2 inches of whey on top, after 7-10 hours at other times. The incubation temp does change some, because the oven with the light on still changes with the outside temp quite a bit. and we have had everything from 45-103F in the past few weeks.

Help me, I'm losing all yogurt enthusiasm.

[MrsKK]

Are you keeping records of your yogurt making?  If you have been, you might be able to look back at what the differences in technique have been and the differences in consistency and flavor of the yogurt and figure out why you aren't able to get the same results all the time.

When I make yogurt, I heat the milk anywhere from 175 to 190 Fahrenheit.  I then take it out of the hot water bath and either just leave it on the counter to cool (when I have the time) or submerge it in a sinkful of ice water if I need to get going.  The constants in my make though come down to the amount of culture I use and the temperature at which I incubate the yogurt.  I use 1 cup of yogurt culture to one gallon of milk (made from a previous batch) and I incubate in a Coleman personal size cooler, filled with 120 degree Fahrenheit water.  I incubate from 7-10 hours, depending on the time of day that everything occurs.

My original culture is Greek Gods Greek yogurt and I end up with really nice, thick yogurt every time.

I hope this helps you out!

[Alice in TX/MO]

I made the best EVER today from my Mini Mancha's milk and the Yogurmet culture.  It's THICK!

I accidentally boiled the milk when heating it.

[tnsven]

I went through this same thing earlier this summer. Not sure why. I think the heat thing is flexible. I shoot for 165-180. I used to just get it to temp then cool it. Now I hold it for 10 minutes. I cool to below 120 before adding the culture, usually in a sink of cool water to speed things up (I always need to get it done with 5 kids around  )  I'm using a purchased yogurt culture, not starter yogurt. If I leave it to incubate too long, it gets a bit sour for the kids.

Now that I'm writing this, I did find that my thermometer was in need of calibration. Perhaps my problem with yogurt earlier this year was caused by this. I was reading UNDER by about 6 degrees. Could this be your problem? Cause if you cool to 110 sometimes, 115 others, or 118, you may be killing some of your starter culture if your thermometer is reading low? Just a thought.

You'll figure it out.

Kristin

[KosherBaker]

Well, I am distraught. I cant seem to get consistent yogurt. How precise does the 185F for 30 min system need to be.

Hi Nitai. I missed this the first time I read your post. Are you holding the milk at over 180F for 30 minutes? I believe this is too long. There are three pasteurization temperatures/methods and 185F is the least desirable of the three. But regardless of that. In the recipes that I've read for yogurt you are simply asked to bring the milk to that temperature and then turn the heat off. In fact many recipes say you can plunge the pot into ice cold water to cool it off immediately. So I don't think you need to hold the milk at 185F for 30 minutes.
Keep in mind I've only been making yogurt at home for about a year now, so I'm no expert. But maybe this is something you can look up in your yogurt recipes/sources.

Help me, I'm losing all yogurt enthusiasm.

Hmmmm, this may be against forum rules. Don't make us contact the authorities. 

... If I leave it to incubate too long, it gets a bit sour for the kids.

Heeeheee, I incubate for about 12 hours, as I like the stronger more pronounced flavor. I use the Strauss Organic yogurt. Trader Joe's sells it under their name. The plastic container is also red and it says European Style Organic yogurt. I too use a cup of yogurt per gallon of milk. In my experience if I hit 180F I can then start to cool the milk down, caveat being I always work with store bought organic milk.

[BigCheese]

The heating is not for pasteurization, but for protein denaturation. You can read about it elsewhere on the forum.

[KosherBaker]

Of course, you are right. I sort of regretted adding the pasteurization bit after I did it. However, in a way this is what pasteurization does also.

In any event all I wanted to say was, check your yogurt making recipes/instruction to see if they in fact call for holding the milk at 185F for 30 minutes. Because, every yogurt recipe I have seen is pretty specific about this not being the case. The recipes I've seen say to heat it up to that temperature, at a specific rate and then immediately turn off the heat. Or even plunge it into an ice bath.

[MrsKK]

Actually, there's been extensive discussion around here about the success with yogurt when maintaining the milk temp at around 185 for 20 minutes before cooling it off.

[KosherBaker]

Actually, there's been extensive discussion around here about the success with yogurt when maintaining the milk temp at around 185 for 20 minutes before cooling it off.

Ahhhh. Thank You Karen. Being a clueless noob I should be more careful about posting.   Sorry Nitai. Hopefully someone more knowledgeable will chime in here, then.

I'm slowly making my way through the archives for the boards here, and am really enjoying it. Hopefully, I'll run into the discussion(s) you mentioned soon as Yogurt is one of my favorite milk products and I make it often.

[linuxboy]

I cover this here:

http://cheeseforum.org/forum/index.php/topic,2924.msg23880.html#msg23880
http://cheeseforum.org/forum/index.php/topic,4079.msg31275.html#msg31275

Well, I am distraught. I cant seem to get consistent yogurt. How precise does the 185F for 30 min system need to be. Sometimes I need to go but I am only at like 175F, so I leave it an extra 10 minutes. There are various small variables like that.

175F isn't enough. Best results are 185-190 for at least 15 mins, and not more than 30.

It would be one thing if the consistency was alittle thicker sometimes, little thinner sometimes, but I get super thick yogurt in 7.5 hours sometimes, and yogurt that never really thickens, or has 2 inches of whey on top, after 7-10 hours at other times. The incubation temp does change some, because the oven with the light on still changes with the outside temp quite a bit. and we have had everything from 45-103F in the past few weeks.

There you have it. Temp is extremely critical. You're dealing with a symbiotic culture blend, whose products and dominance varies extremely even with a 10 degree change. If you get acidophilus dominance, your texture and mouthfeel will be radically different than if you have S. thermophilus dominance.

I can try sending you some cultures with exopolysaccharides that favor a thick mouthfeel if you're looking for a thick gel.

[BigCheese]

I really appreciate the offer LB, but you have done more than enough for me already! I have switched to a cooler with a thermostat controlled heating pad and things have improved. I have also just finished hosting 25 people for 10 days, so when my brain works again, I'll do some better tests and see what the results are. Thanks for everyone's input!