The Roving Brewer: Episode 4

January 2, 2007 at 12:00pm

Author(s): Eric Watson

This is the forth in a series of discussions with our roving brewing expert, Eric Watson. Episode 1 of The Roving Brewer caused quite a stir and brought up a number of questions. We are addressing those question in the next several episodes.

Q: I have always added my first hopping after I have gotten the hot break to be skimmed off by me then added my first hop addition after a vigorous boil and that starts my 60 minute boil time schedule (and reduces the chance of a boilover).

A: Whether you knew it or not, adding the hops after a vigourous boil is attained is what is now practiced in all German professional breweries. It turns out that the albumin (that white scum) entrains hop constituants if it is present. This results in lower hop utilization and a reduction in head retention. In prior German studies, the practice of first wort hopping was thought to impart a "smoother" bitterness. What they did not take into account that this perception was due to a decreased alpha/beta utilization and loss of myrcene, cohumulone and other essentials in the albumin, not the supposed "more gentle extraction." They didn't even measure any other effects... such as head loss! Hard to imagine they made such a bad recommendation given the anal, engineering/quality based beer industry that exists in Germany! The current recommendation is that hops never be added before 10 minutes of VIGOROUS rolling boil has occured.

A 60 minute boil is ok with extract only batches, but for partials/steeps and all-grain, 90 minutes will maximize protein break (assuming the right boil pH). Ensuring this occurs will be worth the extra 30 minutes as it will greatly reduce the conditioning time of your beer, particularly if they are lagers. After all, you want to drink em' faster don't ya?

Q: I have found that even with fully modified malts, a feable attempt at a protein rest will result in clearer beer but clear beer is not my main objective, but nice.

A: What experience & education has taught me is that six proceedural mistakes (or combinations of them) lead to hazes (other than bacterial, dry hop or yeast induced):

1) Not vorlaufing (recirculating) grain runoffs until COMPLETELY clear with NO grain/husk/stach presence.

2) Lautering too quickly, leading to lipid extraction and grain blow-through.

3) Too high of a hot liquor temperature or/and too high of a pH.

4) Not stopping wort collection when the gravity is below 2.5 deg. plato/1.010 SG or the pH rises above 6. (lipid/tannin extraction danger)

3) Inadequate boil and/or at the wrong pH, whether with copper finings or not.

4) Poor primary to secondary to tertiary transfer timing and management. Yes... 2 stages of fermentation, 1 stage of settling. ( I've elaborated on this technique before on this forum, but if you want details on this and why, request it and I'll post.)

5) Inadequate conditioning time.

Q: I've always suspected that the cooled wort needed a bit of aeration but that the yeast was needing oxygen more so & when doing a starter I always splash the starter to aerate.

A: Yes... the yeast need the oxgen, not the wort. If possible, start using a fish pump with an airstone attached to a sterile air filter. Aerate for at least 1 hour and you'll be a believer. I'm using this technique in my brewery (albeit scaled up... my average pitching slurry volume is 5 gallons for ales and 12 gallons for lagers) and at 68 deg. f. my ales ferment to terminal gravity within 5 days and at 49 deg. F. my lagers ferment terminal within 10 days. But, in actuality, I pitch based on viability X cell density, not liquid volume, so those figures are estimates of slurry volumes and can vary somewhat.

An aside... if you use dry yeast, don't aerate at all. They only need hydrated at around 90 degrees for 30 minutes prior to use. Put in the water without stirring for 15 then stir the yeast in and let it settle for another 15. The reason that this is all that is needed is that it takes this long for the yeast to even wake up. And when they do, they need a ton of water to re-expand their cellular walls and functions. During this period, they are not able to uptake oxygen. Besides, if processed by a quality yeast producer, the yeast was dried at the peak of it's vitality when it had a surplus of enzymes. This is not how we receive liquid cultures... they have undergone glycolosis in preparation for dormancy. This is why oxygen/air is recommended. The yeast need it to re-build their cell walls to enter the reproduction phase where they bud. But, any more oxgen has a negative effect on fermentation and ester formation. This is why I recommend using AIR not oygen. It is impossible to get too much oxgen in a starter using air but it is very easy to do so with pure oxygen. If too much oxygen is present in a starter or wort, the media will become toxic to the yeast and will result in substantial yeast death.

The discussion continues! We will pick up with more questions in the next installment.

Here are more articles from The Roving Brewer:

The Roving Brewer: Episode One
The Roving Brewer: Episode Two
The Roving Brewer: Episode Three
The Roving Brewer: Episode Five

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