60 min vs 90 min boil time

[Paul Fraser]

I was wondering what difference there would be between the two and how I should tell when to do a 60 min or 90 min boil?

[Ralph]

I think the difference is around 30 minutes??

 

I dont know the answer to your question and will be interested to see the replies. I guess you would have to allow for the extra 30 minutes evaporation, so if you were aiming for a big beer it could help to get a high OG? I may have also have heard whispers about brighter beer coming from a longer boil... but have no substance to that.

[Paul Fraser]

Ha ha. In beersmith it will automatically change the volume of liquid needed for the boil to achieve the same OG so not sure why I wouldn't just save me some gas and do a 60 min. Will do some researching.

[martin w]

how powerful is your boil? if its a strong rolling boil 60 minutes is probably enough,if its a bit weak 90 would be better,also,grain bills using a lot of pilsner malt generally benefit from a longer boil.during the boil smm(?) is driven off which is the precursor for dms,dms produces cooked corn/vegetable flavours and aromas in the finished beer, once you know the taste you notice it in any beer in which it appears!

there's a bunch of other things going on during the boil such as concentrating the beer,production of melanoidins etc,maybe someone else will chime in and elaborate more.

not sure if i misunderstood your beersmith comment but in software i've used the boil off rate is something personal to your set up,once you know it you normally just set it your preferences.

[Paul Fraser]

Thanks for that Martin. So I guess a 90 min will always be beneficial to finished beer. I've only used my burner once before and boil wasn't all that strong. Have since taken it apart and given it a good clean up so I'll see how that helps it. My boil off rate on beersmith must just be on the default setting. I'm brewing on Sunday so I'll take a note of it and update.

[Dougal]

A couple of things: 

Lightly kilned malts like pilsner can need a longer boil to get rid of dimethyl sulfide (DMS) that leads to a vegetal, "cooked corn" taste in the finished beer. That said, apparently the quality of your boil matters more, and a 90min simmer won't be enough to avoid DMS. 

The second (and more persuasive argument to my mind) is that you get a higher gravity with less grain. For me, the cost of gas is negligible compared to grain. Commercial breweries can be totally different, and I heard of one in the States doing a 30 min boil. The gravity gain is useful though if you want to make an imperial stout.  

 

[Dougal]

Oops! Took too long writing comment. {Ahem} I concur with Martin completely.

[Liam Callaghan]

I have just started running with a 30 minute boil (it is a furious boil) and it seems to be working just fine.  No off flavours that I can tell and the gravity is coming out as expected.  A little light on the first few while I found my feet brewing like that but the last four have been perfect.

I'll ask the guys to check this weekend for dimethyl sulphide flavours as there are a few pro brewers coming to this weekends xmas do.

Thanks for the detailed comments, always nice to learn :)

[Liam Callaghan]

No trace of dimethyl sulphide with a 30 minute boil and both beers were the first kegs to be emptied, 30 minute boil for me from now on.  For session beers anyway.

[Mark Jackman]

That Munich Blonde you brewed was a really good beer.  John Gollics was telling me it was an experimental 30min boil and I certainly didn't find anything there that shouldn't have been.  What was the base malt you used?  Also how quickly do you chill down to pitching temp?    

Anyone wanting to read a bit of the science of SMM and DMS might find this page interesting..

http://beersensoryscience.wordpress.com/tag/dms/

[Liam Callaghan]

Hey mark!

Takes about 20 minutes to chill from boiling to 24 degrees (immersion chiller and agitated wort).  Base malt was pilsner and munich.  20 minute single pitch of hops for flavour, bitterness and low aroma.  The maltiness is what I was after instead of a hop rocket :p

Glad you liked it, this winters are going to be outstanding now I have that one sussed.  Put aside 6 kegs just for that one beer.

[Mark Jackman]

Well with a good amount of pilsner malt obviously that would normally be expected to contribute a lot of DMS in the final wort and the style of beer would have nothing to hide it.  Perhaps a really strong boil helps process the SMM quicker and more evaporates in a shorter period of time.  I've read that DMS has a half-life of 40 minutes but I'm no chemist and I don’t recall tasting any in that beer (as far as I could taste there definitely wasn't) so maybe someone else has an idea what might explain how it all worked out.

I'll look forward to offering some feedback on your future experiments ;)