Author Topic: 2 Questions - Altitude and Substitutions  (Read 2766 times)

Tatoosh

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2 Questions - Altitude and Substitutions
« on: February 08, 2011, 12:48:49 AM »
I have two questions I didn't see addressed in the Wiki, though I have a lot of reading left to do there.

1. I live at 5000 feet.  Boiling temperature is down substantially from sea level.  I have seen one recipe *somewhere* that I can't lay my hands on right now that mentioned altitude.  I think they were talking about making a whole milk Queso Blanco or Ricotta.  They said to heat to 185F at sea level and to 175F at 7000 feet. 

Do any member make cheese at altitude (above 3500 feet) and what changes in heating temperatures do you make?
 
2. Citric Acid powder simply isn't sold here.  But the place is full of very nice local lemons.  What is the guideline for substituting fresh lemon juice for citric acid powder?  I have seen varying reports on other websites as I posted in a different thread.  But is there a reference that is commonly used for that substitution?
 
Right now my cheese making is limited to Queso Blanco and Ricotta until I get some starter and some newer rennet.  I had some success with a Queso Blanco from Carabao (Water Buffalo) milk recently.  One liter produced a bit over 7 ounces of cheese.  I heated the milk to 180F (double boiler) and added 2 tablespoons of lemon juice*.  It came out fairly good, no liquid draining though when I put it in the colander, the curds were fairly firm, but not as tough as some previous attempts.  Quite edible.

However, I am concerned about when I do get supplies and start trying more advanced cheeses, specifically mozzarella, though I hope to do Gouda and Provolone down the road too.  I will be making those at altitude and using the local lemon instead of citric acid powder where called for. 

* I reported 2 ounces in my previous post on a separate thread, but when I checked the graduations on the small measuring cup, it was not ounces but tablespoons.  My bad. 

coffee joe

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Re: 2 Questions - Altitude and Substitutions
« Reply #1 on: February 08, 2011, 09:45:31 AM »
As to your question regarding altitude, the situation is defined by Boyle's Law.
As the altitude increases, the pressure drops so the boiling point decreases. The chemical properties of the coagulation process don't change much due to this, however. You still need the temperature to get the desired results. At 5000 ft, you won't get to boiling below 200ºF so just use your thermometer and aim for the recipe temps. Use a lid as much as possible to maintain as much added pressure as possible and to avoid evaporation of volatiles. Boiling causes other stuff to happen so you will need to keep below a boil.

As to the rest of your question, I will defer to those with more experience.   

Tatoosh

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Re: 2 Questions - Altitude and Substitutions
« Reply #2 on: February 08, 2011, 02:39:24 PM »
Thanks, coffee joe.  Yeah, we don't get to boiling at 200F degrees here, probably closer to 203F or so.  That is 95C and one of the temperatures that a recipe for whole milk Ricotta recommended I heat too.  Now, that Ricotta was a dismal failure.  "Tougher than a junk yard dog" as the Jim Croce song goes.  The milk was from a local dairy and had been pasteurized.  Exactly how it was pasteurized is a "secret" since they don't talk about that.  Just say it is pasteurized, like the process is a secret.  Well, their process is, I suppose.  I am guessing it is a higher temp, shorter time method, but not UHT pasteurization.  But to be on the safe side, I will get their raw milk next time.   

The failure, rather than milk, was likely either the temperature (we went to 95C degrees which is right at the bare edge of boiling here) or it was the amount of vinegar we used.  The recipe called for 1/2 cup vinegar for 10 liters of milk.  Since we were making with 1 liter of milk, we scaled the vinegar back by 1/10th.  118 milliliters of vinegar in a half cup.  I think we may have gone sour there, making the vinegar 18 or 20 milliliters, not 11 or 12 like we should have.  (Dim old oven light going off in head as I type this!) 

We moved away from "whole milk Ricotta" toward Queso Blanco.  Better luck there.  We switched to lemon juice for that.  It was much closer to what I expected.  Not creamy and really didn't need to be drained at all once we spooned it out of the whey.  That may be due to to much agitation while heating.  Or maybe too much lemon juice though I was quite the conservative sort pourer, following advice that only enough to get the curd to separate out.  So I added it by the tablespoon.  Two tablespoons and the curd came out, the whey turned greenish and I stopped.  Still not perfect, but better.  Much better.  Wife brought home some "Pata Tim", a braised pork dish and made soup from the remaining bones.  I  enjoyed sopping up the soup with soft bread and then putting a layer of Queso Blanco on.  Made a great petite meal.

So I won't modify lower temperature points in a recipe, but I will err on the side of caution when it gets around 203F or 95C. I hope to make Queso Blanco, Panir (Paneer?) and Ricotta (whey or whole milk) as additions to pizza and other dishes that benefit from a white cheese. 

Now the remaining Question about acidic substitutions remains.  Lemon Juice in place of Vinegar or Citric Acid Powder.  It would really be great if there was some sort of formula or table to consult when these are substituted in cheese making.   Interestingly, in cooking, vinegar is sometimes substituted at 1/2 the amount of lemon juice.  But for canning, where acidity is key issue and not taste, vinegar is substituted at twice the amount of lemon juice. One website, not specific to cheese, suggested 6 tablespoons of lemon juice to 1 tablespoon of citric acid powder.

So until I can find better information it seems like:

1 tablespoon of Lemon Juice = 2 tablespoons of Vinegar
6 tablespoons of Lemon Juice = 1 tablespoon of Citric Acid Powder

Anyone out there with a PH tester and access to these three ingredients, maybe you could post PH readings? 
« Last Edit: February 08, 2011, 02:47:46 PM by Tatoosh »