We use yeast recovered from one batch to seed the next batch. So every day a new generation of yeast would be used. The yeast evolves over time through natural selection and therefore changes slowly over time. It is also possible that some time there were an infection from another yeast that took over and we just did not notice.
Modern production methods try to reduce the evolution in the microbes we use. The yeast from one batch will get divided into tiny samples that each get frozen. They can then be thawed one at a time and revived in the lab to be used for brewing for an entire month. This means the same generation of yeast can be used to brew the beer for years instead of just a single day.
+1 to this comment. In addition, advancement in all aspects of brewing has led to stricter standards of malting grain and hop processing. Much less our understanding of water chemistry. It's difficult to get a known recipe to perform to flavor profiles in any two (non macro) breweries, much less understand a recipe written for different standards of ingredients hundreds of years ago. It's part of the fun trying to suss it out!
I guess the final question will be is this just what this batch this year tasted like. Without much standardization farming season up river could greatly affect things. One batch may have had just more nitrogen runoff and its not exactly like they sourced another purveyor. Tuesdays batch is Tuesdays batch no matter what went into it.
As someone who made soup everyday for 20 years i would have the aim of making the same soup but one day i made the best batch of cream of broccoli that i just never could replicate for no good reason, not that i put out bad batches, just that one day was perfect for no explicable reason.
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u/Jsr1 8h ago
When did we lose the original recipe?