I think that you are looking for this...
http://byo.com/mrwizard/760.html
When a relatively small weight of specialty grains is steeped in a large volume of water, the result is a very thin mixture. The pH is only slightly affected by the malt (pale malts tend to lower the mash pH during all-grain mashing to about 5.4 pH). This means the pH of the solution during steeping will be higher than the pH of a normal mash, which has an oatmeal-like consistency.
though, he adds a qualification at the end:
You ask whether steeping and sparging released "unwanted tannins" in your beer. For starters, all beer contains tannins. Some tannins are implicated in haze and some lend astringent flavors to beer.
The type most homebrewers are concerned about are those affecting flavor. In any case, it is up to the brewer to decide if the level of tannins in their beer is too high. The (in)famous decoction mash is frequently recommended when a brewer is in search of more malt flavor. Decoction mashes boil malt and — among analytical brewers who are not afraid of rocking the boat with unpopular ideas — are known to increase the astringent character associated with tannins. In general I wouldn’t consider 170° F dangerously high with respect to tannin extraction. However, if you believe your beers may suffer because of too much astringency, consider adjusting your steep pH and lowering the temperature a few degrees
To add my own person experience
When I did specialty grain/extract brews, I used more of a thin steep as mentioned in the first link and never experienced any tannin extraction issues. Of course, you have to take into account my water chemistry to begin with...YMMV, ect.