I heard on one of the Brewstrong episodes that there is a significant difference between mashing and steeping grains, and not all grains can be steeped. But in reviewing my archives I can’t find the exact episode. Does anyone have a link or can speak to this issue. I was discussing at my last HBC meeting, but couldn’t explain myself very well…
A crystal (something with “cara-”) can be steeped since its already had the starch turned to sugar. A highly roasted grain can be steeped since its mostly there to add color and flavor, its starch has been burnt up to a great degree. Any malt that has its starch intact (pils, 2-row, pale, Vienna, munich) needs to be mashed to break down the starch to sugar. You could get some flavor out of it but the starch is liable to cause cloudiness.
I dunno…to me, a mash is just a steep with a controlled temp, time, and amount of water. I certainly don’t see “significant differences”.
…plus some base malt for the enzymes
Yeah, I agree with Denny, mashing is just steeping with controlled temp (pretty important usually), controlled time (lots of leeway) amount of water (a lot of leeway here too).
And like hokerer mentions, base malt to provide enzymes although most malts that require mashing have sufficient enzymes to self-convert.
It’s certainly not anything to stress about (oh how I wish I could have told myself this 15-20 years ago).
If I remember correctly, John Palmer lays out steeping grains in How to Brew as a minimash, but without worrying about insulating the pan.
There are many ways to steep, the one I teach is to do so at 150-155F so the brewer is prepared to move to a partial mash.
There are two ways to brew, simple, which is better to get started, or we can make it rocket science. Good beer is produced both ways.
And you don’t have to load up on the science all at once either.
+1
Is it true, that if your malts are fully modified, then steeping is fine, regardless of the type of malt? And if they’re undermodified, then a mash is necessary?
No
Modification is measured by the length of the rootlet at the start of the “malting” process. 3/4 the length of the gran to the length of the grain is considered fully modified, less than 1/2 is under-modified. This is the process that starts the enzymes that are needed for mashing.
Mashing is the process that converts starches to sugars by utilizing the enzymes formed during the malting process.
If the malts are fully CONVERTED, then they do not need to be mashed.
It appears much of this is semantics.
Based on what I hear gurus talk and write about, you steep when you extract brew with specialty grain and don’t care about converting starches into sugars as you are about to add a potload of sugars in a can or in powder form, and you mash when you brew all grain and convert the starches to sugars yourself. What happens when for how long under which temperature is recipe specific, and there is plenty of overlap. But I think the terminology breaks down that way.
My $0.03
No, semantically, there’s definitely a third very accepted terminology that’s between the two you mention. That’s the “partial mash”. You mash a (relative to all grain) small amount of grains and make up the rest with extract.
An extract with specialty grain conversion. I’ll buy that. So in the end it all comes down to where the sugars come from. I think that was what I was trying to say to begin with…
Or- consider steeping is as much as about “flavor and color” extraction as sugar rinsing. Mashing is the addition of conversion to the process if applicable.
Not exactly. A mini-mash can be done with base grain, it doesn’t have to be specialty grain at all. The important part is that you are holding temp and converting starch to sugar, not what the grains are. Yes, it’s a bit of a semantic point, but it helps if we’re all on the same page 
OK, that was what I was REALLY trying to say… 
A mash includes a steep, but all steeps aren’t mashes. Soaking a pound of specialty grain in 2+gal of 170F water for 20min isn’t going to do much in the way of mashing. I think the advice to teach a version of steeping that is equivalent to a mini-mash, was a good one. Then you don’t necessarily need to worry about whether a grain needs mashed or not, and you’re not going to have pH issues that lead to extraction of undesirable components.