Newby with questions

First,  congrats on your first few bakes.  If you decide to pursue this any further, you really need a digital scale - they can be found for under $20, and it allows you to be much more precise than cups.

1) There are videos where they don't pre-heat the oven.  They put the scored round into a cold dutch oven in a cold oven and increase the covered baking time to 55 minutes, then uncover for browning.  The results in the video look good but it's hard to tell texture.  Anyone have comments?  I'm trying this out with my 4th bake.

I have not done it,  but many here use either a cold DO, or a cold oven, and report the reslts are similar, although the baking time is longer.  I highly encourage you to try it for yourself, I never felt all that comfortable handling a hot DO and loading dough into it.

2) There are

videos where 20 minutes into the initial proofing they stretch and fold the dough in the bowl, working their way around the dough.  Then cover again, wait 20 minutes (an hour in some videos) and do the stretch and fold again.  Repeat for a total of 4 times.  So how does this affect the final loaf?  They say it strengthens the gluten but I don't know what that means in a practical sense.

In general,  if your yeast is doing its thing, you need a strong gluten network to capture the gas to let the dough rise -  think of using helium gas in a balloon as opposed to putting helium gas into a kitchen towel formed in the shape of a balloon -  it won't rise.    Stretch and folds develop gluten, and in fact there are several recipes which use that instead of kneading.  Time can also develop gluten.  Your recipe uses time to develop gluten, so you would probably not want to do 4 S & F and then let it rest overnight.  Whether your loaf would benefit from one or two S & F would depend a lot on your flour, and how long you are letting it rest

3) There are videos where after the first proofing they take the dough and throw it down onto the work surface, maybe a dozen times or more.  Then for shaping they spread it into a rectangle shape  and fold the corners into the middle and a round forms.  So how does this affect the final loaf?

There used to be a preference to "Knock Down" the loaf at the end of what we call the bulk ferment.  Some still do that, others suggest that the dough be handled more gently. In either approach,  there is some manipulation of the dough to move the yeast. As I understand it, the yeast are not very mobile, and it is sort of like putting a horse in a very small paddock - in a short order it will graze all the available food, and will need to be moved to another paddock to graze.  By knocing it down, or a gentle preshape then final shape, we are moving the yeast to a new place to find food.

4) I'd like to make a loaf of rye bread.  Maybe 2 cups of bread flour and one cup of rye flour, .  If I understand correctly (and please correct me if I'm wrong) the rye flower will reduce the rise and not form gluten.  If so, would it make sense to increase the yeast a bit to get more rise?  And would it make sense to use the stretch and fold or stretch and throw down methods to compensate for the lack of gluten in the rye flour?

I don't use rye much , but in general, adding more yeast will not help, the rye will never develop the gluten network to trap the extra gas.  Can't help on the rest of the questions, other than to suggest that if you have a recipe that works, try modest changes and keep notes.  So you might want to start with 50 grams of rye, then next time 100 grams of rye and see how it works.  Once you get a digital scale, you will want to keep it on grams, most recipes here are in grams and it is very simple to convert up or down.  So if a recipe calls for 1000 grams of flour and 650 grams of water, and you want a loaf that is half that size, you just divide all the quantities by 2 , so you would have 500 gram of flour and 325 grams of water - no jumping back and forth between ounces and pounds.

Anyway, thanks for any enlightening you can offer.

Hi Rich! Welcome to the Freshloaf! And congratulations with your first three no-knead loaves.

1) cold oven or cold dutch oven baking. 

a) If your oven is preheated, but your dutch oven is cold, bake as usual. 20min covered and 20 min uncovered. Then see if the color of the crust is to your liking or you want it to be darker. If yes, add 5-10-15 more minutes of baking incovered.

b) If both your oven and your Dutch oven are cold, then place your DO with the shaped loaf inside it in the oven, turn it on and wait until it reaches 425*F which could take 20-30mon depending on your oven, THEN count 30min covered and 20min uncovered baking time. It is that simple.

The results are the same as with baking in a preheated oven in a preheated do, but safer for you since it is easier to handle cold things without burning yourself.

2) Stretching and folding dough as it ferments. What does it do?

a) If your dough is kneaded, then stretching and folding it as ot fetments degasses it somewhat and strengthens its gluten.

When gluten is weak, bread dough resembles soft oatmeal, it flows and does not hold its shape too well. When gluten is strong, bread dough resembles rubber and when you shape it, it keeps its shape as it rises.

b) If your dough is unkneaded, as in no-knead bread,  then stretching and folding it has the same effect as kneading, i.e. mixing ingredients to homogeneity and developing gluten.

Developing gluten means making bread crumb softer with more translucent pores and the crust thinner and easier to chew.

3) After the first proofing, take the dough and throw it down onto the work surface, maybe a dozen times or more.  Then for shaping spread it into a rectangle shape  and fold the corners into the middle and a round forms.   How does this affect the final loaf?

It makes a better bread, obviously. Better crumb, better crust, better taste.

Throwing it down helps degassing and developing gluten further and gives gluten strength. Then, after shaping, it will keep its shape better as it rises and bakes.

4)  The rye flour will reduce the rise and not form gluten. 

Yes. Therefore, you should not expect rye bread to be the same as pure wheat bread. It won't be as tall or as fluffy, although at 30% rye, as in your example of 2cups wheat flour +1cup rye flour, the difference is not that big.

If so, would it make sense to increase the yeast a bit to get more rise? 

No. Increasing yeast is not necessary. If you want your rye bread to rise more, add gluten, i.e. dry gluten flour, to your rye flour. 1-2 tbsp of dry gluten per each cup of rye flour.

And would it make sense to use the stretch and fold or stretch and throw down methods to compensate for the lack of gluten in the rye flour?

Yes. Developing and strengthening existing gluten by doing these things will always help having taller and tastier loaves even if 1/3 of all flour was replaced by non-gluten flour such as rye, oats, etc.

Basically, if a 100% wheat loaf has 13.5% gluten forming proteins from bread flour, then a 70% wheat loaf (with 30% rye flour added) will have

0.7 x 13.5% = 9.5% gluten forming protein, which is ideal for breads as tall and fluffy as French bread, baguettes, etc. 

Best wishes,

m.

Rich,
   Welcome to TFL.

   If you don't already have this book, it is currently on sale for only $4 in Kindle format,  "The New Healthy Bread in Five Minutes a Day," by Francois and Hertzberg.

This is their much improved edition with measurements in cups, grams, and ounces.

See my review at https://www.thefreshloaf.com/node/70286/free-or-discounted-kindle-bread-ebooks-4#comment-513051

It has a formula for a 33% rye loaf, using VWG as Mariana suggested.