I have done a tone of research on this topic... a ton!! and as with most things on this forum I have a slightly different OPINION on reusing yeast. It is an opinion that I am working on backing up with fact (will let you know in a few years after I have reused my yeast enough times to form some reliable conclusion) , but have not gotten there yet so let me tell you what I think, why I think it.
First of all here are the arguments against reusing wine yeast that I have seen (I am sure there is more)
1. a pack of yeast is only $.99
2. fruit deposits lots of sediment
3. unlike beer or cider the higher ABV of wine will stress the yeast out
4. as the yeast adapt this WILL produce off flavors
5. Using fresh wine yeast cultures is how it has been done, is an established practice and is how it should be done.
I also want to note before I go on that most, if not all of these arguments seem to come from people that have not tried it. So there argument is based on hearsay.
My thoughts on these arguments
while a pack of wine yeast does only cost $.99 as was pointed out in this thread "you can get 4 vials of yeast that can be used 4 times (for a total of 16 uses from one packet of yeast). This would save this poor college student ~$16." but it could be better than that, each time you wash a batch of yeast you could in theory break it up in to 4 more starters so the first reuse gives you 4 starters, the second reuse would give you 16 starters, the third would be 64 starters and the fourth would be 256 which is a grand total of 340. Now I understand that having that much yeast in jars in a fridge is not practical but it does show that a person could easily save more than $16.00 by reusing yeast.
The argument that fruit deposits fruit sediment, while being true, doesn't hold water for me. There are a couple reason for this, first of all beer making is not a sediment free process, and I can't imagine that wine produces that much more non yeast sediment than beer. second the idea of reusing yeast involves washing the yeast which will remove much of the sediment, that is the point in washing.
The argument that the higher ABV of wine will stress out the yeast makes sense, stress yeast CAN produce off flavors but doesn't always. To me that argument is a reason FOR reusing yeast. yeast are highly adaptive creatures and as their environment changes so do they. They grow and change to best suite the world they live in. in other word if you use the same yeast over and over in similar wines they will adapt to the temperature of where you keep your fermenters, they will adapt to the types of fruit you us, the types of sugars you use, and the level of acidity yo like your wines at. In other words as you reuse them you will end up with a yeast that is suited to specifically to what you are doing. This is why cider makers are fond of wild yeast from the orchard and its apple presses, especially if that orchard has been in business for many years. Why because those yeast are adapted to eating apple sugars, and thus produce a superior apple product. The same could become true when reusing wine yeast. If you are making the same thing over and over that yeast will reproduce and become adapted to what you are making which will reduce its stress and in theory produce a better product.
This leads me right in to the next argument that as the yeast change it WILL produce off flavors. That is a false statement. It may produce off flavors but the wine may also get better with future generations of yeast. You really won't know until you try it. For me I make wine 1 gallon at a time. I may have 10 different batches but they are all 1 gallon. If one of them turns out with off flavors than than I am out 1 gallon of wine no big deal... or maybe those off flavors will make it not as good as previous batches but still good so I am not out a gallon I just have something that might benefit from more aging, carbonation or blending . I guess what I am saying is having a few batches that are just OK or even not good is a risk I am willing to take because there is a chance I can end up with something that is even better than normal. Don't get me wrong if you make an annual batch of wine that involves 20 pounds of an expensive fruit or has a lot of time and effort involved than by all means use a yeast that is guaranteed to produce a good product.
"Using fresh wine yeast is how it has been done, is an established practice and is how it should be done." I hate this argument!!!! It implies that perfection has been attained and that there is no room to make something better. If you fail to challenge the status quo than you cannot grow. I am not suggesting that we thumb your nose at established practices because that would be change for the sake of change. Established practices are there because they have proven themselves to be effective and are a nice fall back position. but to assume there is not a better way out there just weighting to be discovered seams to me to be a missed opportunity.
Like I said before this is all my opinion based on the research I have done. I have come to some logical conclusions based on other people observations and my own understanding of how yeast grow and reproduce. I am going to start reusing my yeast and see how it goes. I have four batches going right now three of which use a store bought wine yeast and one that is a washed wild cider yeast. The three wine yeast batches are a white, a red and a cider and I plan on reusing them on similar type wines. if it works out than great, if not, than I will have a few wasted batches down the road. The best part about it is I will have some definitive answers as to my results in yeast washing. I will keep this forum informed as I go.
