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Fermentatie

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Verstokte brouwers hebben het wellicht wel eens meegemaakt: een gestokte vergisting.
Shocktop is een bier, waar brouwers over praten over het toegepaste gist (WY1010?) en of dat uit het flesje is op te kweken.


 I popped the lid to check it out and there isn't any krausen visible (see picture below). Could the beer have completed fermentation that quickly? Would that be bad? (www.homebrewtalk.com/showthread.php?t=418568)

Lagers should start in the low to mid 50's (12-14c) and ferment there until about 75% complete. Some strains then require a "diacetyl rest" to prevent off flavors from diacetyl. This is achieved by warming the beer into the 60's (16-18c) for a few days to complete the fermentation. The step is often not necessary with modern yeasts and quality ingredients, but many brewers still swear by the practice. The beer is then gradually dropped a few degrees per day until just above freezing and "lagered" for several weeks or even months. Where ever you got the advice to ferment a lager at such a warm temperature has no credibility, as this goes against everything I've ever read about lagers... (www.homebrewtalk.com/showthread.php?t=385060)

How important is the fermentation temp after you've hit gravity?
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After active fermentation there is actually some benefit to letting the temp rise a bit to keep the yeast happy and busy doing their thing. I generally don't do too much worrying over temps after the first 10 days or so as there is really no concern over off flavors developing at that point, it is more about conditioning and the yeast cleaning up.
For bottle conditioning and carbonation around 70 is ideal and I have had bottles go at 72-74 without any issues. Once carbonated and conditioned though I am sure to relocate the bottles to my colder basement where I store them at 60-65.....The most crucial time to monitor your temperature is during the growth phase of the yeast. During that period of lag time, the yeast are reproducing to the necessary level to ferment your specific wort. It is during this phase that the yeast produce most of the esters and phenols that will flavor your beer. This also means that "close to equally" important to your yeast growth phase temp is your pitch size. Can you make good beer pitching too little yeast and allowing your beer to set at 74/75 degrees during the growth phase? Sure. Will you make a beer that will win a major competition? Likely not. Go to Mr. Malty.com to make a proper yeast starter to active them as well as grow your pitch to proper size as well as do your best to get that temp down a few degrees if you are looking to brew competition quality beer. I personally like to pitch at 5 degrees below my intended fermentation temp and set my temp controller to allow a free rise through the growth and lag phases. This helps to stave of diacetyl as well as keeping my esters and phenols in check. Belgian strains work specifically well in those lower to mid 70's temps but Id still try to start around 65 and allow a free rise. A simple solution to not having a fermentation fridge is to get a plastic tub with water in it and throw a few frozen water bottles in throughout your fermentation to help....There could be a theoretical danger in pitching too low (especially with an ale strain) but 5 degrees won't hurt. There is a tremendous danger in pitching too high due to the potential of excessive ester and phenol production. In the first 72, I keep my beer at the desired fermentation temp. Past the first 72 hours, temp control becomes less important...but fluctuations can lead to issues (www.homebrewtalk.com/showthread.php?t=333693).

Ja, fermentatie is een complex proces... ook voor een gewoon (commercieel) biertje.

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