[Pi]

67% in the grist along with some flaked maize and some carahell 10l.

[tygo]

I've made brilliantly clear lagers using 6-row and corn with a single infusion mash so I would say that it does not need a protein rest.

[snowtiger87]

It depends on what other fermentables you have in the mash. Most people don't use 6-row unless they are using some other fermentable that has low or no diastatic power, like corn or rice. Together these ingredients benefit from a protien rest.

[nateo]

According to Noonan, the weighted average of the grist should be around 10% protein. For all malt beers, a weighted average over 12% may cause haze or runoff issues. For beers using large amounts of adjuncts, too little protein may not provide adequate head, body, and yeast nutrition.

So a beer with 100% Maris Otter at ~9% protein would be ideal for a single infusion.

A wheat beer with 50% wheat malt (15%) and 50% American Pale (11%) would have an average of 13% protein and would benefit from a protein rest.

An adjunct-heavy lager with 50% 6-row (13%) and 50% rice syrup (0%) would have an average of 6.5% and would need additional protein to make an acceptable beer.