Is it true that if you pitch a healthy amount of Yeast into a lager’ at 44F an let the heat from fermentation raise the temp to 50F an hold it there for 4 week’s . The reason for the 4 weeks is i hear that you don’t need a d-rest
Depends on the yeast. I always do a d-rest. Raise it to about65for a week.doesn’t hurt anything.
Yes and No.
Yes many will chill to around 46F and it will only raise around 4f at a max, so you will reside around optimum for most strains of 48f during primary.
Primaries typically will last 1.5-3 weeks and you will want to raise up towards 60-66F for a D rest with most all strains after 75-80% of fermentation is complete. Then crash cool after D rest is complete and lager at 32F for 30-90+ days depending on beer type.
If you leave the beer at 48f for a month you will have used up all available yeast consumables and they will have mostly flocced out of suspension and any diacetyl will possibly be re consumed during lagering but the biggest thing is sulfur not facilitated out of the wort in the d rest stage also will form by-products called mercaptans that will not age out gracefully and will wreck a brew if sulfur(temporary) is left to form mercaptans(permanent).
Sulfur is a natural by product of lager yeast where not formed with ale strains.
Each specific lager yeast has its own highs/lows for Ester/higher ester formation, diacetyl, VDK and sulfur. You just need to be aware of the strain you are using and its own set of requirements. There are a few strains that produce very little diacetyl or sulfur and even when using these types I still do a D-rest for all the other beneficial aspects.