I will move this question to a separate thread as it seems to be an interesting question...
Statistics: Posted by lupulus — Tue Jan 09, 2018 9:25 am
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I remember the interview. I thought at the time that it was with ale yeast as there was no true lagering period. I think this was when he was working at Bass (not a study). The way I recall the process being described is that there was a process to reduce VDK levels (I think it was a small temperature increase for a few days), followed by a 2-day crash at -1C to reduce yeast and particulate matter and then off to packaging. I do not recall whether they filtered. So, he could have been talking about an process to drop particulate matter including ale yeast.
My question was comparing lagering at 3C, which should increase metabolism of the yeast vs 0C which should have a faster particulate matter drop.
I may be wrong but I think it was the diacetyl podcast...
Statistics: Posted by lupulus — Mon Jan 08, 2018 9:34 am
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Statistics: Posted by lupulus — Sun Jan 07, 2018 11:56 pm
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Why 3C? Yeast would certainly be more active, but I would have thought that clearing would take longer. Maybe it is the other way, and they clear faster because they run out of nutrients/ substrate faster at 3C.
What do you all think? I will be doing some reading in the following days.
Statistics: Posted by lupulus — Sun Jan 07, 2018 10:13 pm
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Statistics: Posted by Techbrau — Sun Jan 07, 2018 8:07 pm
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Yeast and Yeast Management
This is still the single most significant important part of the process.
I've always favored the cold fermentation with lagers, and have subscribed to the mantra that the more delicate the lager, the more disciplined you must be on the cold fermentation profile. I, too, moved moved away from the spunding valve, and instead simply begin dropping temperature at around 2% over EVG, then rack to a keg at 1% over EVG. It results in considerably less yeast in the keg and more in the cake in the fermenter. I have noticed that later generations of yeast begin to drop clearer and faster, which is quite likely due to brewhouse selection since the yeast from the cake is reused and the settled yeast from spunding is discarded. My solution is to use 50% of new cells from a stir plate and 50% of cells from a previous batch. I put back a small sample from every stir plate starter so that I always have a healthy, clean sample to return to should something go wrong. It's not as good of a long-term solution as slants, but I've not had any issue with yeast that gets attention every 6 months or so.
Also, I make batches 2-3L larger than needed for the keg so that I can pitch, let the cells beginning budding and then at 24-48 hours pull off the volume needed for my next starter. This is essentially top cropping for lager yeast, as I am only collecting the live, viable yeast (no trub or settled matter) and the many new daughter cells are present and waiting to be grown up to full size in an aerated, nutrient rich environment. I find it makes consistent and reliable yeast that work well with the Narziss cold fermentation profile, and in theory my pitches can be used forever, as they will always have adequate new cells removed before flocculation occurs to prevent the brewhouse selection typically observed from cone to cone pitching between batches 5-15.
My new system is 50L, so I anticipate doing a lot of split batches and playing around with a lot of lager strains. I've tried most of them with a single batch or two, here and there, but not with split batches with a dialed-in, inert system. I view this as starting with a clean slate. So far, 835 has never let me down and has been a brewhouse workhorse. I have no complaints about the strain itself. But, it's also a hobby, and I enjoy the freedom of not having to brew the same beer the same way every single time.
Malt
Best is best. I try others for fun, but none match the quality, consistency and flavor as those from the German maltsters.
I really like the flavors of the brühmalz better than the karamalz, but they seem much more delicate and perishable and their oxidized forms can be offensive to the palate. If I'm going to brew a beer that will be consumed quickly and without packaging, heat cycling or travel, then I use the brühmalz. Clean peaks theory in recipe development still works for me.
SMB
It is an elegant solution, but not a magic wand. Use it as you would any tool in the toolbox, but it won't correct for other flaws in your process or system. It is very easy to produce matchstick beers, so tread carefully, know your system and ferment accordingly. Fermentation temps and pitching rates can correct for too much SMB in the mash and boil. I find 10-25 mg/L to be adequate.
AA
Ascorbic acid can produce the same effects as SMB, only it requires much higher concentrations, and it can be a double edged sword. That said, it has a place in my mash cocktail, as it only makes sense to me to take advantage of the natural enzymes and mechanisms in place in the malts to utilize AA for preventing oxidation. I find 10-25mg/L to be adequate. In the future, I anticipate sauergut completely replacing AA in the mash.
BB
Brewtan B has a place in my mash cocktail simply for its potential for preventing superoxide formation. I've never been a fan of adding significant amounts of purified tannins during the boil, as I work very hard to prevent tannin extraction during all other phases of my brewing process. I find 10-25 mg/L to be adequate in the mash. If I used tap water, then I would likely use 50-75 mg/L to mitigate the iron and heavy metals from the miles and miles of pipe my water travels to get to me.
Sauergut
This area needs more attention in my brewhouse, but I much prefer the natural, biological solution to acidification over mineral acids. It also brings with it a slew of organic acids, nutrients and natural antioxidants that make it the perfect compliment to SMB and inert brewing methods. Using AA or CA to initially drop the pH in sauergut may be an elegant way to load the SG with antioxidants and prime the pH for lactose fermentation.
Boil
The boil is a fickle mistress. Once you've produced those delicate, fresh-baked, aromatic characters of warm bread, you know how easily they can be lost in the boil. Once the end of boil wort tastes as delicious as the mash wort, then I know I am doing it right. I take my time getting my wort up to a boil, and I like to keep my total evaporation rate single-digits low.
Thank you all for a great 2017, here's to 2018!
Statistics: Posted by Owenbräu — Sun Dec 31, 2017 11:52 am
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