Really sour yogurt?

[Minamyna]

Hello

I have been making quite a bit of yogurt with varying success. I made some slightly sweet vanilla flavored yogurt twice once by adding sugar and once by adding maple syrup. I was surprised that it wasn't super sour. I think I made batches with both goats milk and cows milk and the super sour latest batch I used was cows milk.

Well I decided to get more ambitious and make coffee flavored yogurt. I brewed some coffee and added some to both batches and some sugar. I at this point was eating so much very sour yogurt that I had bad heartburn for around 2 days. SO I decide to let these sit in the fridge for a bit I pulled them out and checked the pH and they are at 4.63. Seems a little low?


Any advice? Should I just start over with new starter? Use goats milk (maybe my goats milk has less lactose)? This might be a linuxboy question, but will adding sugar cause the yogurt to get more sour (more sugar for the bacteria to break down?)

Thanks in advance.

edited to add: I looked up the pH of yogurt and someone thought it shoudl be between 4 and 4.1. Why does this taste so sour to me?

[DeejayDebi]

I find my home brewed yogurt far less sour than the store bought stuff. How old is you starter and is it from an older batch of yogurt or the powdered commercial stuff?

[Minamyna]

Well good question. So I was using brown cow starter, which I love but it doesn't even come out of their cups very solid sometimes so I switched to a small 6 oz cup of Stoneyfield and I used half about 3 days before and then it sat uncovered in my fridge for like 3 days.....

SO I used that for one batch, then for the other batch I used the some of the yogurt that I had made with the first Stoneyfield batch, so it was second generation yogurt starter (to me anyways).

I was thinking about buying some of the "sweet" yogurt culture from The Cheesemaker.

[linuxboy]

Can you post your make process (especially temps) and generational propagation technique and the culture mix in those yogurts?

[Minamyna]

I put 1 quart of milk into a old clean yogurt container, and put in ~1/3 c strongly fresh brew coffee, and a half a vanilla bean, and about 1/4 c maple syrup and about 3 oz of Stoneyfield plain yogurt then I put it in the yogotherm overnight maybe 10 hours. Then I put it in the fridge. I didn't test the temp because its a salton yogutherm.... isn't its job to maintain the correct temp for yogurt?

[DeejayDebi]

It's gennerally best to make the yogurt first then add flavorings after the make. Many of the other chemical could affect the outcome.

[Minamyna]

Yeah I thought that might be true. Sugar as well? How do they get it so solid in the cup thought? I thought most yogurt was cultures in cup. i bought some brown cow yogurt yesterday. So creamy and smooth, not at all acidic, didn't give me heart burn....

[MrsKK]

The yogurt you buy in the store has thickeners added to it, something you are not doing when you make yogurt at home.

Do you know how warm your yogurt maker gets?  When I make yogurt, I use a Coleman personal sized cooler, filled with hot tap water (about 120 degrees Fahrenheit).  I make a gallon of yogurt, heating the milk to 180-185 degrees, then cooling on the counter until it comes down to 110-115 degrees.  Then I add the culture (I've re-cultured for about 8 months now and it is still really good yogurt).  I make culture a pint at a time, removing the cultured milk to a pint jar, well sealed, and put it in the Coleman along with the gallon jar.  I add about a cup of sugar and a half teaspoon of real vanilla extract before sealing the jar up again.  I leave it in the cooler for 8 hours.  I've found that more time than that results in a tangier yogurt.

You might just try shortening the time in the yogurt maker to see if you are culturing it for too long.  Also make sure that the culture you are using is kept well covered and in a very cold part of your fridge to keep it from degrading or getting contaminated.

Good luck and let us know your progress.

[Minamyna]

I am borrowing a Salton yogurt maker from my aunt who lives across the street. I have no idea what temps it gets to, but she told me that between 6 and 8 hours was right, I may have left this one overnight which for me is 12, maybe its as simple as that.

I have to travel for the next couple days, but when I get back I will jump back in. Does the time matter depending on the amount of yogurt you are trying to make?

[MrsKK]

I wouldn't think that the amount of yogurt would affect the time for culturing, as a larger batch requires a larger amount of culture.

[linuxboy]

SO I decide to let these sit in the fridge for a bit I pulled them out and checked the pH and they are at 4.63. Seems a little low?

No, isoelectric point of milk is 4.6. Coagulation usually happens somewhere around 4.7-4.8. Your pH is within a normal range, but it could be higher.

This might be a linuxboy question, but will adding sugar cause the yogurt to get more sour (more sugar for the bacteria to break down?

Not exactly, no. There's residual lactose in yogurt, the sugar is not the limiting factor - pH is. Bacteria will slow down in more acidic environments, and they do so at different rates. Meaning some, like bifidum, tolarate lower ranges, all the way to 3.5, while others stop around 4.5.

In your case, I suspect it was either the balance of bacteria strains changed because of your temps (optimal growth temp differs with the strains), or that you cultured for too long.

[Minamyna]

Well thanks for looking at my problem. I bought some "sweet" culture from the cheesemaker. I will try that. I will have to find out what the pH of that brown cow yogurt I like. The only problem is I bought cups and ate them both...