Ss Brewing Technologies Giveaway!

Home Brew Forums > Home Brewing Beer > All Grain & Partial Mash Brewing > Really useful info from a commercial brewer
Reply
 
LinkBack Thread Tools
Old 11-30-2012, 05:03 PM   #1
BOBTHEukBREWER
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2008
Posts: 544
Liked 5 Times on 5 Posts

Default Really useful info from a commercial brewer

The short extract below is lifted from Thornbridge Brewery (UK) website - -
thornbridgebrewery.co.uk

I mentioned oxygen earlier. This is used initially by the yeast to grow. We add a certain amount of yeast to our wort. Pretty much, the stronger the beer will be, the more yeast we add initially. Let's take Jaipur, for example, where we add around 7 – 8 million cells of yeast per millilitre of finished wort. A lot of yeast! The yeast is floating around in a super rich environment of nutrients, mostly in the form of sugars, amino acids and peptides that the cells start voraciously feeding on (well absorbing through their cell walls at any rate) and undergoing a process called budding. This is where the yeast cell (referred to as the mother cell) creates another yeast cell (referred to as the daughter cell). Something called Yeast Viability is important here. This is one of the first laboratory checks we do on the yeast. We take a sample of the yeast that is going to be added, or pitched, into the wort, we count and calculate how many cells are present in one gram of yeast (not all by eye of course... it's usually between 500 and 2500 million cells in a gram!) and we also stain the sample with a special dye called Methylene Blue. If the yeast cells are healthy, an enzyme present inside of the cell will change the dye from blue to colourless. We calculate the percentage of cells that are able to do this and express it as Yeast Viability. We really want this to be greater than 90% otherwise we're just adding dead yeast to the wort and this can potentially cause off-flavours.

So we have yeast, oxygen and wort. The yeast is increasing in biomass (usually by anything up to 5 times) by a process called budding and using up nutrients to get its own nitrogen and carbohydrates and fatty acids and anything else it needs to grow. But what happens when the oxygen is all used up? This is when the yeast switches its mode of metabolism from aerobic to anaerobic. Anaerobic means in the absence of oxygen and it is here that the yeast begins the actual fermentation and sugars are converted to carbon dioxide and alcohol. Without boring you all to tears (I'm sure I can see some already... right at the corner of your eyes...) effectively, sugar is absorbed into the cell and broken down by a series of enzymes into the aforementioned carbon dioxide and alcohol. As well as this, there are a bunch of side reactions which both use and yield energy for the yeast cell and also give an interesting array of flavours to the finished beer. Fruity esters or flavour active ketones (such as the rich,intensely buttery diacetyl) or sulphury compounds or even heady, harsh, fruity or bitter fusel alcohols. They all blend together to provide the final beer flavour. Some of these are good and sought after, others not so much and a brewer puts all of his or her training and understanding into keeping some of these metabolic by-products out of the finished brew.

The rest of the process is described just as well.

__________________
BOBTHEukBREWER is offline
Revvy Likes This 
Reply With Quote Quick reply to this message
Old 11-30-2012, 05:12 PM   #2
Revvy
Post Hoc Ergo Propter Hoc
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Revvy's Avatar
Recipes 
 
Join Date: Dec 2007
Location: "Detroitish" Michigan
Posts: 40,804
Liked 2733 Times on 1640 Posts
Likes Given: 3485

Default

Good info. But this should be in the fermentation and yeast section rather than the AG section, since it pertains to all types of brewing not just Ag. Or the Brew Science section...A lot of extract brewers who might be interested in this info will prbably not see it since they don't read this section of the forum.

__________________

Like my snazzy new avatar? Get Sons of Zymurgy swag, here, and brew with the best.

Revvy's one of the cool reverends. He has a Harley and a t-shirt that says on the back "If you can read this, the bitch was Raptured. - Madman

I gotta tell ya, just between us girls, that Revvy is HOT. Very tall, gorgeous grey hair and a terrific smile. He's very good looking in person, with a charismatic personality... he drives like a ****ing maniac! - YooperBrew

Revvy is offline
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
New Brewer in Japan looking for local info colincbn Introductions 11 10-31-2012 04:13 PM
Converting from Home Brewer to Commercial Brewer FensterBos General Beer Discussion 10 03-16-2012 02:37 AM
brewer.info down? bengerman General Chit Chat 0 09-03-2011 05:20 AM
New brewer asks for info curtisj Beginners Beer Brewing Forum 4 01-23-2011 03:52 PM
A question about commercial brewing...for the commercial brewer... Thor the Mighty Commercial Brew Discussion 1 04-07-2010 01:25 AM