halvor
a most elusive fish
Splendid, Steve. Thanks! Will read with interest on time not paid for by my employerHi @halvor
Maintaining fermentation temperature used to be a black art for the home brewer. Waiting for the wort to cool to the correct pitching temperature, waiting for the little beasties to start working, watching for the airlock to start bubbling away etc etc. My understanding is that the primary fermentation is an exothermic process. The internal temperature of the fermenter can be as much as 5.5°C above ambient conditions, just due to yeast activity. Thus it is very important to keep the fermenter in the proper temperature range; so that with a normal vigorous fermentation, the beer turns out as intended.
I have just completed modifying an old fridge into a fermentation chamber by adding a small tubular heater and controlling the temperature with one of these https://www.amazon.co.uk/All-Purpos...e=UTF8&qid=1478160814&sr=8-4&keywords=inkbird.You will also need a plastic enclosure to house the unit, a power lead to connect the unit to the mains electrical supply , two socket outlets for connecting the fridge and heater, some flexible cord, cable grommets and some electrical connectors. Plug the fridge into the cooling socket and the heater into the heater socket, set the desired control temperature and the tolerance +/- temperature difference you require and set it to work. Tape the sensor to the fermenter and cover in bubble wrap, close the door and wait. You would of course need a very large fridge in which to ferment 60L of beer.
Another thing that I have learned is that the fermentation of malt sugars into beer is a complicated biochemical process. It is more than just the conversion of sugar to alcohol, which can be regarded as the primary activity. Total fermentation is better defined as three phases, the Adaptation or Lag-time phase, the Primary or Attenuation phase and a Secondary or Conditioning phase. The yeast do not end Phase 2 before beginning Phase 3, the processes occur in parallel, but the conditioning processes occur more slowly. As the majority of simple sugars are consumed, more and more of the yeast will transition to eating the larger, more complex sugars and early yeast by-products. This is why beer improves with age to a degree, as long as they are on the yeast. Beer that has been filtered or pasteurized will not benefit from aging. fermentation is not a single / simple phase process but i multifaceted and highly complex. See below
In order to accommodate this for the first time I am trying a variable temperature fermentation schedule similar to this:-
As for metallic taste are you brewing from liquid malt extract, dried malt extract or all grain. I would think that tinned malt extract could taint your finished product.
- Start at 20°C for 36 hours, right in the middle of the temperature range for your yeast to make it easy for them to start up and multiply.
- After 36 hours, when your beer is bubbling well, drop the temperature to reduce ester formation. Set the profile to be at 17°C at 3 days.
- Keep the beer at 17°C for 3 days, but fermentation is slowing down.
- Yeast is more active at higher temperatures, so slowly raise to 22°C over 5 days: as the yeast consumes more and more complex sugars, it can do this at a higher temperature.
- After reaching 22°C, keep it at that temp for 2 days, before cold crashing at 3°C.
It sounds like you are using kits, Try adding some fresh hops in the form of a hop teabag to the hot wort or dry hopping to the secondary fermentation prior to bottling. This should improve your beer, providing you like hops of course.
Hope this all makes sense and helps.
