Mesa, ?? about boiling time and hops

Physics, chemistry and biology of brewing. The causes and the effects.

Moderator: slothrob

Mesa, ?? about boiling time and hops

Postby mje1980 » Sat Aug 21, 2004 4:31 pm

I have just read in another post that it is beneficial to boil the wort for at least 10 mins before adding hops, and that the boil should be at least 90 mins. Why is this, i did not want to hijack another thread, if there is another post about this topic, could you please refer it to me, or explain the main benefits please. I usually boil for 60 mins, and i have just bottled a batch where i tried F.W.H. Also, for a finished volume of 18 litres in my fermentor, i have to boil at least 27 litres (accounting for the dregs at the bottom of my kettle and evaporation), i want to know how much preboil volume i should aim for to counter the 90 min boil?

Any advice is greatly appreciated :)
Here's to cleansing ales, lovely lagers and lacy glasses!
mje1980
 
Posts: 7
Joined: Fri Aug 13, 2004 5:04 am
Location: Aussie

Re: Mesa, ?? about boiling time and hops

Postby Mesa Maltworks » Sun Aug 22, 2004 12:02 pm

"I have just read in another post that it is beneficial to boil the wort for at least 10 mins before adding hops, and that the boil should be at least 90 mins. Why is this?"

The reason you should wait 10 minutes after attaining a VIGOROUS boil prior to adding hops is related to albumin formation that entrains hop constituents resulting in less utilization and negative effects on head retention. By the time a vigorous boil has been maintained for 10 minutes, the protein chain bonds that form albumin will have broken and will no longer be of concern. You then start the time on a 90 minute boil, so your actual total boil time is 100 minutes.

"Also, for a finished volume of 18 litres in my fermentor, i have to boil at least 27 litres (accounting for the dregs at the bottom of my kettle and evaporation)"

With the supplied statistics, you are expecting around a 33% loss in volume. I typically experience a 10% loss in volume due to evaporation and a 8% loss due to trub and equipment losses. So my total is 18%. I believe that you can collect more wort from your equipment even if you increase the boil time by 30 minutes. If you try to siphon completely off the trub in the kettle it is still in an expanded state, taking up more volume than if it is decanted from when cooled and bound by collagen from finings. A lot of brewers assume that irish moss and the likes increase kettle settling of proteins... wrong! They only begin to work effectively when the wort temperature is below 85, so it is a COLD break aide. The only reason it is added in the last 15 minutes of the boil is to release the collagen gel from the seaweed. This is why at the brewery, I bleed off the trub from the fermenter cones 12 hours after being filled. This practice can be replicated by siphoning the wort off the trub in your fermenter just as fermentation is beginning. This will ensure that your fermentation will have very little kettle derived trub in it which will result is a more stable, quicker conditioning and better tasting beer. An additional benefit is that your wort will only contain the most viable and vital yeast population. Any yeast that flocced out early on is essentially dead and does you no good laying on the bottom of the fermenter! This step is especially crucial if you repitch yeast slurry or culture starters.

I believe that this regimen will give you the results you desire even though you increased the boil time.
Make your next beer (or spirit) a local one!!!!

Eric Watson
Head Distiller & Brewer

Seven Fathoms Rum
Georgetown, Grand Cayman
Cayman Islands
User avatar
Mesa Maltworks
Strong Ale
Strong Ale
 
Posts: 474
Joined: Tue Sep 11, 2001 11:16 pm
Location: Georgetown, Grand Cayman Island

Postby JimK » Thu Aug 26, 2004 10:48 am

That makes a lot of sense to me now, having just finished my 20th batch. I was wondering why the trub would take forever to settle out. I may go back to starting in my origingal plastic pail for overnight, and then racking off in the morning. That way I can get it sealed faster than I have been(waiting for everything to settle out. My only worry would be, at times the fermentation starts earlier than others, and when it is going good, there is nothing at the bottom of the fermentor. Also would it be necessary to wait until the fermentation actually begins before doing this?
JimK
 
Posts: 3
Joined: Thu Aug 26, 2004 10:38 am
Location: Reedsburg Wi


Return to Brewing Science

Who is online

Users browsing this forum: No registered users and 3 guests

cron