Yeast, is 1 pack enough experiment.

As a follow on from my earlier post regards to how much yeast is needed to brew a batch of beer, I have experimented with the notion that 2 packs is better than 1. I am referring to dry yeast, so packs that contain 10/11 grams of yeast, such as US-05, S-04, BRY-97, the types of yeast lots of brewers are using. What i have done then, is to split a batch and brew them with the corresponding yeast amounts. To make life easier for myself, I used a Fresh Wort Kit, from All Inn Brewing. Their Golden Ale was the chosen brew.

I split the FWK into 2 batches, each 10 litres. So not quite half batches but close enough for comparison. For this trial I used US-05 dry yeast. Into 1 batch i put 1/2 pack of dry yeast, sprinkled on top and the other batch had 1 pack pitched onto it. So essentially I had the equivalent of 1 pack VS 2 in a full batch scenario. I needed to split into 2 small batches to fit both into my temp controlled fridge and also 2 FWK's was not economical. The result is that the smaller batches had comparative cell number ratio's to doing larger batches.

I set the fridge at 19.8° and allowed the yeast to do its thing. After 12 hours the larger pitch had healthy signs of fermentation where the smaller had very little. Hydrometer samples taken each 48 hours indicated that the larger pitch dropped 2 points lower in the first 48 hours then hit terminal gravity around 24 hours earlier than the smaller one. Both brews were allowed to sit for another 5 days to ensure complete brewing. Hydro samples indicated both had finished at the same SG; so the larger pitch had made no difference, which was to be expected, it still only attenuates to a certain point and with the same batch of yeast any other outcome would have been a surprise.

So after a cold crash, bottling and allowing to carbonate naturally in bottles I did a comparison.

I found that the 2 pack beer had a smoother finish than the 1 pack beer, which was a little tart and bitey on the tongue. The 2 pack beer also displayed a better head and retention, though not a drastic difference the appearance was more pleasing than the 1 pack. The aroma was similar and both beers showed similar levels of clarity. For me, in my tasting the 2 pack beer was of a better quality and much more enjoyable.

I have repeated this tasting comparison about 2 weeks later after the bottles have conditioned a bit longer and still found the same results.

I have received a few knockers online due to the testing method and not doing 'blind tests' with numerous tasters; and while I agree that would be nice,I have enough confidence in my own palette to know what i am tasting.

CONCLUSION: I now have even more belief in using 2 packs of yeast as opposed to 1, if you are using dry yeast. I still recommend rehydrating for best cell health, but for numbers and better beer, use 2 packs.