Sorghum is a grain that is gluten free if not contaminated somehow, perhaps by shared equipment in processing.
While all grains belong to the grass family, sorghum is a distant cousin to the gluten containing grains of wheat, rye, barley, and oats. Sorghum contains a type of storage protein, called a prolamin, just as the gluten-containing grains do, but the sorghum prolamin has different amino acid sequences and is different enough that people with gluten sensitivity don't react to it.
So if you are on a gluten free diet and are interested in using sorghum syrup, or see sorghum on a label, in theory it should be fine.
Sorghum doesn't itself contain gliadin/gluten, but sorghum flour is often contaminated with gluten, according to a recent research study. Sorghum flour was found to contain 234 ppm of gluten, presumably either from wheat plants growing in a sorghum field at time of harvest, or from contamination at the mill.
Here's a link to the abstract of the research article: http://www.ncbi.nlm.nih.gov/pubmed/20497786.
And here's a link to a website discussing it: http://suite101.com/article/celiac-disease-diet-study-many-gluten-free-grains-contaminated-a243716
Yes, which is why it's a popular flour substitute for gluten-free baking.
Well you can still use flour just not wheat flour and it will be gluten free
Bob's Red Mill Corn flour is gluten free.
flour has more gluten; spelt is gluten free.
Yes, but you can buy gluten-free flour.
Yes. Unbleached flour is a pale tan color.
There is - in the UK, look out for "Doves farm" brand gluten free flour. (Same shelf as regular flour in the supermarket). It is a mixture of (various types of) gluten free flours (rice, soy, quinoa etc...), designed to be used in recipes in the place of normal flour. In specific gluten free recipe books, "rice flour" is usually used instead of a mixed "gluten free" flour.
yes if you get a gluten free muffin mix
In a traditional quiche, the only ingredient that will contain gluten is the flour with which the pastry case is made. To make a gluten free version, purchase a bag of gluten free flour and use this for the pastry.
If pure, no. Check label for additives that may contain gluten
Most gravy is not gluten free because of the use of white flour to thicken gravy. There are alternatives to this such as using a gluten free flour or cornstarch to thicken your gravy. There are many recipes for gluten free gravy online, just google it.
Brew it from something that does not contain gluten - the simplest but messiest would be gluten-free flour.
Flour and water, or you can use corn starch and water. If gluten free just use a gluten free flour alternative.