Partially cover to maintain boil? No DMS problems?

[zgo]

I just bought this great 6 gallon pot for my 3 gallon batches. This evening I've been experimenting to see how long it takes to get to boil on my gas stove and what the evaporation rate is.

While it achieves boil on my stove pretty well (30 minutes), once I take the lid off it cools a bit and settles at 209/210 degrees.

I'm assuming getting to 212 is important and 209/210 won't do it...right? So is there any harm in covering it halfway? As long as there's somewhere for the evaporation to go, I won't have to worry about DMS?

Btw, I live in an apartment building, so a turkey fryer is out of the question.

 

[billl]

It needs to be boiling. There is no need to measure the temp of the boiling wort, just make sure it is boiling.

You can keep the lid partially on, but it is more tricky than just letting some steam escape. Most of the steam will hit the lid and condense. If that condensation drips back into the wort, you are setting yourself up for DMS issues. You would need to balance the lid so that anything dripping from it drips outside the pot.

 

[tedclev]

I often keep the lid partway on during a boil. Even with condensation dripping back into the kettle, I've never had any DMS problems. Although, with pilsner malt I would be more cautious.