Large scale hop utilization

Hi,
New member on the forum here and long time beersmith user.  I was fortunate enough to win first place at a homebrew festival this past fall with an IPA.  Part of the prize was getting to brew the award winning beer at the local brew pub. 

Scaling up the recepie to a 7 barell (217 gal) Peter Austin Brewhouse.  We nailed the gravity at 1.060.  Hop additioins were scaled up along with everything else from a 10 gal batch to 7 barell.  I understand now that hop utilization is higher with batches over 20 gal, but the question is how much higher??  At 10 gal. the IBU would be around 60.  No adjustments were made from the linear scale.  Can anyone tell me what I have done?  What IBU will this beer likely be?  What should I adjust hop utilization for a 7 barell system?  Does anyone have a chart that shows how much efficiency increases as you scale up over 20 gal batches?
Thanks. 

We have a couple "Pro" brewers on the forum. Maybe they can pitch in and shed some light on this.

Cheers
Preston

Unfortunately, there is no magic chart for that. Utilization will increase; sometimes dramatically. I am assuming the kettle at the brewery is direct fired? If it is, then I wouldn't expect to get more than 10% more utilization. With a kettle that is steam fired ( steam jacketed kettle bottom and sides ) you can get anywhere from 10-20% increase. If the kettle utilizes a calandria you can expect even more ( 20-25% with an internal calandria and 25-35% with an external ). It all really depends on how vigorous and even your boil is. With a direct fired kettle you get hot spots, very rarely does the entire volume of wort roll the entire time. Generally it rolls vigorously in one area, then moves, etc. With a steam jacketed kettle, it is heated from all sides and tends to roll fairly vigorously on the outsides of the kettle. With an internal colandria, the wort actually moves through convection up the calandria in the center of the kettle ( which is heated with outgoing steam from the steam jackets ) up against a splash guard and back down into the wort. The external calandria is simply a steam heat exchanger that the wort is pumped through.

"Some breweries have a boiling unit outside of the kettle, sometimes called a calandria, through which wort is pumped. The unit is usually a tall, thin cylinder, with many tubes upward through it. These tubes provide an enormous surface area on which vapor bubbles can nucleate, and thus provides for excellent volatization. The total volume of wort is circulated seven to twelve times an hour through this external boiler, insuring that the wort is evenly boiled by the end of the boil. The wort is then boiled in the kettle at atmospheric pressure, and through careful control the inlets and outlets on the external boiler, an overpressure can be achieve in the external boiler, raising the boiling point a few Celsius degrees. Upon return to the boil kettle, a vigorous vaporization occurs. The higher temperature due to increased vaporization can reduce boil times up to 30%. External boilers were originally designed to improve performance of kettles which did not provide adequate boiling effect, but have since been adopted by the industry as a sole means of boiling wort.

Modern brewhouses can also be equipped with internal calandria, which requires no pump. It works on basically the same principle as external units, but relies on convection to move wort through the boiler. This can prevent overboiling, as a deflector above the boiler reduces foaming, and also reduces evaporation. Internal calandria are generally difficult to clean."

Sorry about the long post, but I hope that helps you understand the differences in utilization. Like I said before, there simply isn't a magic formula.

Darin

Thanks for the response Darin.  The kettle is a direct fired whirlpool so the wort is rotating all the time as it boils.  The beer has been on tap now since Christmas and it's almost gone.  Just from taste testing and comparing it to the 10 gal batch in my keezer I would say we ended up with something like a 70 - 80 IBU.  I also noticed that the brewery version is slightly darker and more carmalilzed which I think improves the malt flavor and balance (more agressive boil than I get at home).  It's a bit more of an IPA than we planned for but awsome just the same and has been very well received by the patrons of the brewery.  I am thinking I will send out a bottle of the original version and the brewery version for comparison testing and find out what the increased utilization really was.  This way I can adjust equipment option in Beersmith to account for it in the future.
Thanks again for the response.
Neil

Spectacular response Darin! Thank you!

Neil,

Is your 10 gal recipe anywhere in the downloads areas? Love to try it! Care to share?