Hi Charcutebrew,
You wrote:
Another way to ask this, I guess, is "Does all dried meat ferment?" I would think not, since when I make jerky the meat just dries out. Is the salami-making process different because of the hang time?
You are correct - all dried meat does not ferment. However, the difference between the jerky and salami does not depend solely on "hang time". It depends upon several things, but the two concerning us mostly are: (1.) the `water activity` (abbreviated Aw) which is the measurement of how tightly the "water available to bacteria" is "bound", and the (2.) the
"potentiometric hydrogen ion concentration" 
(abbreviated pH), which is a measurement of acidity. More about that in just a minute.
First, its important to understand that the USDA has written,
"A potentially hazardous food does not include a food with a water activity value of Aw 0.85 or less".Meat with water remaining in it will quickly spoil. As a sausage drops from Aw 0.99 to Aw 0.85 (dehydration), it is protected from
campylobacter at 0.98, from
E.coli at 0.95,
salmonella at 0.94,
clostridium perfringens at 0.93,
listeria at 0.92 (as well as others), then a drop all the way down to 0.85 must occur to halt the very resilient
staphylococcus aureus. This dehydration is usually accomplished fairly quickly to snuff out the bacteria as swiftly as possible.
When we make a
`fermented` type product, salt is initially part of the recipe and is the meat`s only immediate protection against pathogenic bacteria because we purposely "start to spoil" the meat (in a controlled fashion) by indeed
slowing down the dehydration. Salt does not destroy bacteria. It limits the "available" water to pathogenic bacteria by "binding" it. This allows beneficial bacteria such as lactic acid-producing
lactobacillus and
pediococcus, the time, nutrients, and humidity to work their magic by producing lactic acid, thus reducing the pH factor, therefore increasing the acidity (which creates the "tangy" flavor in salami).
Bear in mind that most bacteria are destroyed from 130°;F to 165°;F. However, spores and toxins of bacteria such as
clostridium botulinum, clostridium perfringens, bacillus cereus, and
staphylococcus aureus, are destroyed at much higher heat, at about 240°; F. However, there is yet another element to help us destroy spoilage and pathogenic bacteria besides heat and water binding. It is acidity. In chemistry,
potentiometric hydrogen ion concentration is abbreviated pH. What's this?

Shucks pards, I "aced" college chemistry... mostly because I intimidated the teacher with my garlic jerky breath!

Uhhh... Roughly, pH is the measurement of acidity or alkalinity in any substance using a scale from zero to fourteen. Pure water is said to be very close to neutral, having a pH measurement of nearly 7.0 at 77° F. Foods with pH less than 7 are said to be acidic, while foods having a pH greater than 7 are said to be alkaline or "base". Note that as we
lower the pH factor, we
increase acidity. Are microorganisms able to survive inside acidic foods?
Not when the acidity is increased in a sausage by a drop below about 4 pH., depending upon the specific microorganism we are referring to. Some are more resilient than others.
You also wrote:
So... can a salami just dehydrate & not ferment?
If the salt content of the sausage is over 3.5%, yes it can, as that much concentration may destroy
beneficial bacteria as well. But there is another point you should be made aware of. The finishing point of a salami has nothing to do with "hanging time". It has everything to do with the final pH of the product, or the final point of dehydration as indicated by specific water loss, no matter how mush time it requires.
You also wrote:
I'm also a bit confused about the use of DQ #1 & #2. In the "some good salami" thread Chuckwagon says that you can't hot-smoke meat cured w/#2, that you must have #1 only. But in the sausage safety thread he says that because smoked/cooked sausages are prepped below 150*F they must be cured w/nitrate/nitrite cures... which to an idiot novice like me sounds like using #2 for smoked cured meat. Can someone please tell me what I'm obviously missing?
OK Charred Dude Brew Man, I didn`t say can`t hot-smoke meat cured with #2. What I said was that I disagreed with Ruhlman saying that it was optional to hot-smoke this particular recipe. I qualified my statement by saying Cure #2 is for DRY-CURING ONLY. And it is! I stand by my remark. Here is the quotation I made on June 5th:
I wrote:
On page 186 of Ruhlman`s book, he tells you in instruction #6 that it is optional to hot-smoke this particular recipe. I disagree strongly as a recipe containing Cure #2 is for DRY-CURING ONLY. In order to qualify this recipe for hot-smoking, it MUST contain Cure #1 only. He makes no mention of that fact.
JBK101 is correct. The following is an excerpt from this link:
http://wedlinydomowe.pl/en/viewtopic.php?t=4794
Cure #1 is used to cure all meats that
require cooking, smoking, and canning. This includes poultry, fish, hams, bacon, luncheon meats, corned beef, pates, and many other products.
Note that Prague Powder Cure #1 in the United States, contains 6.25% sodium nitrite (NaNO2), and 93.75% sodium chloride (salt). As this formula contains no sodium nitrate (NaNO3),
there is no waiting for nitrate to be broken down into nitrite and it is effective immediately in curing meat. In the United States, Cure #1 is manufactured using one ounce of sodium nitrite added to each one pound of salt. When used in the curing process, only 4 ounces of cure is added to 100 pounds of sausage. Two level teaspoons will cure 10 lbs. of meat.
It is important to note that in various countries, the formula for nitrate and nitrite cures may differ. For instance, in the United Kingdom, Prague Powder # 1 (Cure #1) is popular, with 5.88% sodium nitrite, the remainder being salt.
Cure #2 is used in
dry-cured sausages only, where curing
time allows the nitrate to gradually break down into nitrite. Cure #2 in the United States, contains 6.25% sodium nitrite (NaNO2), 4% sodium nitrate (NaNO3), and 89.75 sodium chloride (salt). Why so much nitrate? Remember, it is actually nitrite reducing to nitric oxide that cures meat. After two weeks dry-curing, only about a quarter of the 6.25 % sodium nitrite remains in the meat. Nitrite is simply too fast. In salamis requiring three or more months to cure, a certain amount of sodium nitrate must be added to the recipe to break down over time. Since
micrococcaceae species are inhibited at low pH, sausages relying on nitrate reduction must be fermented by a traditional process. Therefore, nitrate is still used by many dry sausage manufacturers because nitrate serves as a long time "reservoir" of nitrite.
Note that in other countries, the formula varies. In the United Kingdom, Prague Powder # 2 (Cure #2) is available with 5.67% sodium nitrite, 3.62 sodium nitrate, the remainder being salt. The strength of nitrates and nitrites themselves do not vary. It is the amount added to a sodium chloride (salt) carrier that makes a cure stronger or weaker in comparison to others. One MUST look at the label to be safe. In Sweden, folks call their product Colorazo at 0.6% nitrite. In France, it`s Sel nitrite` at 0.6% nitrite. In Poland, the nitrited salt cure Peklosol is available at 0.6% nitrite, and in Germany, it is Pokelsalz at 0.6% nitrite content in salt. As you can see,
Prague Powder Cure #1 in America is ten and a half times stronger than European cures, with the exception of some of those in the UK.
One curing agent must never be confused with the other within any recipe and one certainly must not be substituted for the other.
Best Wishes,
Chuckwagon