Otto Von Blotto Posted February 11, 2016 Share Posted February 11, 2016 This was posted over on AHB by user Feldon, and I found it a really interesting read: I like that video - well illustrated and straightforward approach. One thing I do disagree with though is this: he says that when it comes time to take a jar of washed yeast out of the fridge to pitch into a new batch of wort you should let the yeast first come up to room temperature (see about the 11:30 mark in the video). His reasoning is to prevent "shock to the yeast" by chucking fridge temp (~4C) yeast slurry into relatively warm wort. I understand his reasoning because gentle changes in temp are regarded as better practice than sudden shocks which can cause the yeast to over or under-produce various biochemicals. However' date=' from reading various bits and pieces on yeast and how they recover from dormancy (eg. as a result of drying or low temperature storage) it seems it is now considered best practice to pitch the cold washed yeast directly from the fridge into the wort. To do otherwise might result in major yeast carnage. The reason for this is the yeast, as they go into dormancy (eg. due to drying, low temp, or lack of food), produce large amounts of sugars. These are stored internally within the cell walls of the yeast as a future energy reserve for when the yeast will eventually exit dormancy when the external environment becomes less hostile (eg. wetter, warmer, or more food about). Glycogen is an important sugar that is stored. But another one is trehalose - a molecule of which is made by the bonding of two glucose molecules together. Trehalose is thought to form a supporting gel-like substance in the dormant yeast cells which protects its organelles from getting damaged when the cell distorts due to dehydration, and protection from osmotic pressure when its moved from a dilute environment (eg. a jar of water) to a more concentrated environment (eg. fresh wort). By letting the jar of washed yeast come up to room temp before pitching, the yeast cells exit dormancy (wake up) and become biologically active again, and this requires an immediate need for energy. It was long thought that it was the sugar glycogen that was first used by the yeast for energy as they came out of dormancy. But it is now understood that the yeast consume the trehalose first - and in doing so the yeast become very vulnerable to the osmotic potential of wort very quickly. So if you leave the washed yeast to come up to room temp for hours, when you pitch it into the wort much of the yeast's reserves of the protective trehalose are gone and many of the yeast cells will be torn apart by the wort that can invade the cells by osmotic pressure. This also has implications for those who chose to rehydrate dry yeast before pitching. If you are going to do it you have to do it properly or yeast will die on pitching. I think dry yeast makers say rehydrated yeast must be pitched within 30 minutes or so (while there is still enough trehalose remaining in the yeast cells to protect the yeast). My 2 cents, but for an expert opinion, this is an old post by Dr Clayton Cone of Danstar Yeast in response to a question about cold pitching of yeast: I have not seen any studies done using this protocol. If I had to take a guess it would be centered around the Trehalose content in the yeast cell. Trehalose seems to be an all around stress related factor. Almost immediately upon the cold storage of the yeast, trehalose begins to build up to help the yeast to adapt to its new environment. Upon pitching this stress factor assists the yeast to adapt to its new environment; warmer temperature and higher osmotic pressure. If the pitching yeast is allowed to warm up for any appreciable time before pitching the carbohydrate reserve, trehalose being one of them will be quickly used up as an energy source. The yeast would then take a longer time adapting to its new environment in the wort thus increasing the lag phase. Something similar happens when using Active Dry Yeast. The factory builds into each yeast cell an abundance of the stress factor; trehalose. Our recommendations is to rehydrate the yeast in warm water and pitch into the wort (or must) within 30 minutes, because the yeast will begin to metabolize its carbohydrate reserve including trehalose immediately upon reactivation and weaken the yeast if it is not in the presence of a new supply of energy. It will have also used up the stress factor that would have assisted it in adapting to the new osmotic environment. I am sure that there is more to the explanation than I have given. [/quote'] Link to comment Share on other sites More sharing options...
N1KK0 Posted February 11, 2016 Share Posted February 11, 2016 Excellent article, makes a lot of sense and very helpful (though I now feel much less than great about my rehydrated yeast taking ~40mins to be pitched yesterday!!!! :-( - much thanks for sharing. Link to comment Share on other sites More sharing options...
Hairy Posted February 11, 2016 Share Posted February 11, 2016 That's an interesting read. I never waited more than 30 minutes for dry yeast to rehydrate anyway because I am impatient. Seems impatience pays off. Link to comment Share on other sites More sharing options...
ChristinaS1 Posted February 11, 2016 Share Posted February 11, 2016 Yes, that is an interesting read Kelsey. Thank you for sharing. I have read that quote of Dr. Cone's before, but the other part is new to me. In terms of rehydration they say the temperature of the yeast should be within 15F of the wort before pitching (warm yeast into cooler wort). In terms of washed yeast/saved slurry maybe the thing to do is to allow the yeast to warm up for 30 minutes, then start adding small amounts of wort to the yeast until the temp difference is within 15F of the wort? This mirrors rehydration instructions, but in reverse. It does not make sense to me that temperature shock can only happen in one direction, going from warm to cold. I suspect it can happen from cold to warm as well....I know that if I get really chilled and step into a warm tub, it feels hot, whereas if I was not chilled and stepped into the same temperature water it would just feel warm. Link to comment Share on other sites More sharing options...
Beerlust Posted February 11, 2016 Share Posted February 11, 2016 Interesting. Do let us know how your 'cold pitch' Saison turns out. Cheers, Lusty. Link to comment Share on other sites More sharing options...
Otto Von Blotto Posted February 11, 2016 Author Share Posted February 11, 2016 It does not make sense to me that temperature shock can only happen in one direction' date=' going from warm to cold. I suspect it can happen from cold to warm as well....I know that if I get really chilled and step into a warm tub, it feels hot, whereas if I was not chilled and stepped into the same temperature water it would just feel warm. [/quote'] Indeed, it does feel hotter if you are cold when stepping into a warm bath. However, to me this is much more inviting and comfortable than being hot and stepping into an ice bath. I suspect it is similar for yeast. I'm going to experiment with this theory on my next few batches. I'll put the cube in the brew fridge with the yeast starter on the morning of pitching day (if it fits ) to bring it down to pitching temp but I will leave the starter in there too. Then on my work break I'll get my old stir plate out and stir the yeast up after decanting most of the spent beer, and pitch it straight into the wort, then see how the lag time and fermentation goes. At the moment, I'm not really getting any significant reductions in lag time from making starters as opposed to simply re-hydrating dry yeast, perhaps it is due to allowing them to warm up prior to pitching. Link to comment Share on other sites More sharing options...
Hairy Posted February 11, 2016 Share Posted February 11, 2016 It does not make sense to me that temperature shock can only happen in one direction' date=' going from warm to cold. I suspect it can happen from cold to warm as well....I know that if I get really chilled and step into a warm tub, it feels hot, whereas if I was not chilled and stepped into the same temperature water it would just feel warm. [/quote'] Indeed, it does feel hotter if you are cold when stepping into a warm bath. However, to me this is much more inviting and comfortable than being hot and stepping into an ice bath. I suspect it is similar for yeast. Because of the nervous system of the yeast Link to comment Share on other sites More sharing options...
ChristinaS1 Posted February 11, 2016 Share Posted February 11, 2016 It does not make sense to me that temperature shock can only happen in one direction' date=' going from warm to cold. I suspect it can happen from cold to warm as well....I know that if I get really chilled and step into a warm tub, it feels hot, whereas if I was not chilled and stepped into the same temperature water it would just feel warm. [/quote'] Indeed, it does feel hotter if you are cold when stepping into a warm bath. However, to me this is much more inviting and comfortable than being hot and stepping into an ice bath. I suspect it is similar for yeast. Because of the nervous system of the yeast Ha-ha, right you are Hairy. I will be interested in to hear your test results Kelsey. Link to comment Share on other sites More sharing options...
shitsngiggles Posted February 11, 2016 Share Posted February 11, 2016 Great read, Thanks for sharing Kelsey So for us simple folk with the training wheels on still in nappies doing K&K ... it seems best for us rehydrators would be to prep the brew, allow the dry pack to return slowly and naturally to ambient room temp then rehydrate at pitching/FV temp and pitch within 30 mins yeah ...? I have also read conflicting info on feeding rehydrated yeast, some said do with same sugars as in the brew, other say malt, others say don't at all ... ?confused? ... if feeding whats the best (recommended) procedure? Link to comment Share on other sites More sharing options...
Otto Von Blotto Posted February 11, 2016 Author Share Posted February 11, 2016 Great read' date=' Thanks for sharing Kelsey [img']smile[/img] So for us simple folk with the training wheels on still in nappies doing K&K ... it seems best for us rehydrators would be to prep the brew, allow the dry pack to return slowly and naturally to ambient room temp then rehydrate at pitching/FV temp and pitch within 30 mins yeah ...? I have also read conflicting info on feeding rehydrated yeast, some said do with same sugars as in the brew, other say malt, others say don't at all ... ?confused? ... if feeding whats the best (recommended) procedure? I imagine with dry yeast that you would allow it to come up to room temp first before re-hydrating it. But yes the idea is that it should be pitched into the wort within 30 minutes. The pitching cold yeast theory is more aimed at yeast slurry that has been saved from a previous batch/starter and stored in the fridge and is being pitched into a batch of wort. Or even a starter that has been cold crashed. If you are simply re-hydrating the yeast in water then feeding is unnecessary, and not really much different to simply dry pitching it straight into wort. All you need to do is boil some water, then let it cool to the manufacturer's recommended re-hydration temp, throw in the yeast, let it sit for 10-15 mins, then stir it for a few mins and pitch into the batch. If you're making yeast starters these are a mini wort that is used to grow more yeast from the original packet. This is a different process to re-hydration. Generally made from malt extract and water, although some brewers do use wort from the actual batch that it will eventually be pitched into. It's not advisable to use things like dextrose or table sugar to make starters. If you are making one with dry yeast, be sure to re-hydrate it as per above before pitching into the starter. Christina I certainly will report back on my results, I will probably do a few brews this way first though just to get a bit more 'data' on how it affects the lag time and fermentation etc. Cheers Kelsey Link to comment Share on other sites More sharing options...
shitsngiggles Posted February 11, 2016 Share Posted February 11, 2016 I imagine with dry yeast that you would allow it to come up to room temp first before re-hydrating it. But yes the idea is that it should be pitched into the wort within 30 minutes. The pitching cold yeast theory is more aimed at yeast slurry that has been saved from a previous batch/starter and stored in the fridge and is being pitched into a batch of wort. Or even a starter that has been cold crashed. Cheers Kelsey Ahhh yes now the whole thing is making more sense now .... wasn't sure what "washed yeast" was but now I'm understanding it is' date=' or similar to a yeast slurry .... (insert noise of penny dropping) So probably not something I'll be doing while I'm still doing heaps of different K&K brews, I'll just stick with rehydrating for now, I can't see much benefit in doing starters for these brews I'm looking at, might be the odd recipe that may call for it I guess? But at least am now a bit more informed [img']biggrin[/img] Good to know that what I have been doing was right though - Thanks Kelsey. Cheers Justin Link to comment Share on other sites More sharing options...
Otto Von Blotto Posted February 11, 2016 Author Share Posted February 11, 2016 I would suggest that a starter would benefit every batch, but, that doesn't mean that you need to jump in and start making them yet either. Re-hydrating and pitching dry yeast packets each time will work fine as well. I harvest my yeast from my starters rather than the main batch, so that is one reason I make them for every batch. It's a very easy way of re-using yeast that does away with all the rinsing and washing and shit that the "traditional" method needs. The other reason, the more important of course, is to ensure adequate numbers of healthy cells are being pitched. A third reason, or by-product, is that it tells you whether the yeast are viable or not before they're thrown into the main batch, although in almost every case they are. Link to comment Share on other sites More sharing options...
shitsngiggles Posted February 11, 2016 Share Posted February 11, 2016 Thanks again Kelsey - I can see the benefits in doing it, healthier yeast, more heavily populated and working etc. I should probably have been a little clearer when I said "I can't see much benefit in doing starters for these brews I'm looking at" was more meant at each brew I'm doing at present is using different yeasts, of course I can still do starters but there is no point in storing up a bunch of them because it could be a long time before I use that yeast again if at all ... and the wort will be different. So From all of this brilliant knowledge ... I'll start trying a few one shot starters, probably more on the heavier/complicated or "yeast sensitive" brews to help my experience along. I've just had a hell of a time with that Honey Wheat ... I bet a starter would have helped this one along .... still tasting good though! It seems like the OD of Honey (1.4kg) turned the yeasties environment hostile once the ABV picked up stalling at 1.020, I kicked the temp up to 21 then I rehydrated another yeast and pitched with a gentle stir and away we went to about 1.016 and stalled again so I frantically tried getting an energiser as suggested by Christina but couldn't get one so tried rehydrating and then killing an old yeast as nutrient with a few raisins and another stir hoping it might pick up again and it did, made it to 1.009 and then my LHBS dude had finally got some energiser for me so I made it up as per directions and pitched it before going away for 3 days. Highly likely finished at 1.009 calculated FG is 1.008-12, given the run of stalls i thought probably wouldn't hurt giving it a hit of energiser I'll get to check it tomorrow night, I'm expecting it to be ready to CC. Link to comment Share on other sites More sharing options...
Otto Von Blotto Posted February 11, 2016 Author Share Posted February 11, 2016 I should probably have been a little clearer when I said "I can't see much benefit in doing starters for these brews I'm looking at" was more meant at each brew I'm doing at present is using different yeasts' date=' of course I can still do starters but there is no point in storing up a bunch of them because it could be a long time before I use that yeast again if at all ... and the wort will be different. [/quote'] I would agree with this sentiment that there isn't much point in storing them all. It is for this reason that I only have 2 or 3 different yeast strains stored at any one time, otherwise they just get forgotten about and die. That said, I do have a jar of Wy2001 Urquell yeast that has been in there since mid October, as I haven't brewed a pilsner since then. In mid-December I made an 800mL wort in a small flask, and pitched the yeast into it (after decanting most of the beer off it), then once it had fermented out, returned the whole amount back to the jar, where it has been sitting ever since. This will keep it alive until I use it properly again (I'll be doing another one shortly as it is getting up to 2 months again), which is partly experimental as well - I want to see what impact these mini-starters to keep it alive have on the outcome of a proper batch once I brew another pilsner. For reference, the jars I use have a capacity of about 950mL. Sounds like you've had a fair bit of issue with that wheat beer there. Hopefully it is all ok now though! I'm having a similar issue with an English ale which I'm using Wy1318 London Ale III yeast in. Predicted FG is 1.011, but it's stuck on 1.017 at the moment after 7 days. I'll check the SG again tomorrow (day 9), but I'm half tempted to simply crash chill it anyway, and then stick the resultant surplus bottles straight in the fridge after 2 weeks to prevent them blowing up if it's not finished. I really don't have time to wait for the stupid thing to dawdle along to the predicted FG, if it even gets there anyway. Interestingly, the last brew I used this yeast on also finished higher than predicted. It was my red ale, the predicted FG was 1.010 and it finished at 1.014. I think I might ditch this yeast after the next batch I use it in and try another one. With all this waiting around I might as well just brew lagers. Cheers Kelsey Link to comment Share on other sites More sharing options...
ben 10 Posted February 12, 2016 Share Posted February 12, 2016 Hmm, I'll try this tomorrow and pitched cold yeast slurry into an ambient temp saison and see how we go. Link to comment Share on other sites More sharing options...
Otto Von Blotto Posted February 12, 2016 Author Share Posted February 12, 2016 Be sure to let us know how it goes Ben. I'm gonna make up another one of those 800mL mini worts for the Urquell yeast tomorrow then go off on a bike ride while it cools down. When I get back I'll take the yeast from the fridge and chuck it straight into the wort and see what happens. Link to comment Share on other sites More sharing options...
shitsngiggles Posted February 12, 2016 Share Posted February 12, 2016 I really don't have time to wait for the stupid thing to dawdle along to the predicted FG' date=' if it even gets there anyway. Cheers Kelsey[/quote'] Yeah I know how ya feel .... my Honey Wheat has screwed up my schedule .... Damn it! although does taste like its worth the wait. With that brew being in the FV for over a week longer than planned coupled with my wife deciding she likes my my beer has almost run me out, time for another FV, will probably look it brewing warmer temp brews like Saison in the second FV as it will be a while before I can look at getting a second fridge. Link to comment Share on other sites More sharing options...
Beerlust Posted February 12, 2016 Share Posted February 12, 2016 Hmm' date=' I'll try this tomorrow and pitched cold yeast slurry into an ambient temp saison and see how we go.[/quote']Good luck with it Ben. If the yeast goes on to ferment out the brew without issue, it may dispel a lot of this yeast temp shock related chatter. I wish you well. Lusty. Link to comment Share on other sites More sharing options...
SRN Posted February 12, 2016 Share Posted February 12, 2016 Hmm' date=' I'll try this tomorrow and pitched cold yeast slurry into an ambient temp saison and see how we go.[/quote']Good luck with it Ben. If the yeast goes on to ferment out the brew without issue, it may dispel a lot of this yeast temp shock related chatter. I wish you well. Lusty. The idea of cold pitching yeast is not meant to dispel the idea that rapid temp changes can be bad for yeast. Its not one or the other. Its more a matter of deciding, as a brewer, which is the best of two evils - temp shocked yeast that might reproduce poorly or give off bad flavours; or temp stable yeast that have lost most of their trehalose and are therefore weakened and vulnerable when pitched into wort. Link to comment Share on other sites More sharing options...
headmaster Posted February 12, 2016 Share Posted February 12, 2016 i had read that pitching cold into warm is ok,so I started doing that, pitching my harvested yeast in to ales at 18 to 20c with yeast slurry at 2.5c, and for lagers 12c yeast at 2.5c. have done this for my last 6 batches and in all cases they have taken off very quickly, within 6 to 12 hrs rocking along. in most cases i am pitching 200 to 400ml of compacted yeast less than 30 days since harvest. works very well for me so I will continue to do this. i found that if i let it warm up, i had issues with co2 coming out of solution and the passata jars doing a mt Vesuvius.. Link to comment Share on other sites More sharing options...
Beerlust Posted February 12, 2016 Share Posted February 12, 2016 Hi SRN. The idea of cold pitching yeast is not meant to dispel the idea that rapid temp changes can be bad for yeast. Its not one or the other. Its more a matter of deciding' date=' as a brewer, which is the best of two evils - temp shocked yeast that might reproduce poorly or give off bad flavours; or temp stable yeast that have lost most of their trehalose and are therefore weakened and vulnerable when pitched into wort.[/quote'] My interest in this cold vs warm pitching really starts & ends on whether it works or not. Past that I have no real interest in the chemical war going on behind the scenes. I look at it much like if I was going to bet on horse. I don't really care if the horse was fed well that morning, or even if it was fed at all, only on whether it is expected to run well or not. Thanks for the info though. Lusty. Link to comment Share on other sites More sharing options...
Otto Von Blotto Posted February 12, 2016 Author Share Posted February 12, 2016 i had read that pitching cold into warm is ok' date='so I started doing that, pitching my harvested yeast in to ales at 18 to 20c with yeast slurry at 2.5c, and for lagers 12c yeast at 2.5c. have done this for my last 6 batches and in all cases they have taken off very quickly, within 6 to 12 hrs rocking along. in most cases i am pitching 200 to 400ml of compacted yeast less than 30 days since harvest. [/quote'] That's probably a product of the amount of yeast being pitched as much as not letting it warm up first although in saying that once I let my starters crash chill I've probably got around the same amount of yeast in the bottom of the flask. However, your experience does follow along with the theory of pitching cold yeast into warmer wort resulting in a reduced lag time compared to letting the yeast warm up for a few hours first. Definitely keen to experiment with this, and tomorrow's mini-starter for my Urquell yeast will be the first test. Link to comment Share on other sites More sharing options...
ben 10 Posted February 13, 2016 Share Posted February 13, 2016 whether it works or not. Tried it today. I'll let you know what happens. Link to comment Share on other sites More sharing options...
Beerlust Posted February 13, 2016 Share Posted February 13, 2016 Tried it today.I'll let you know what happens. Was it pitched straight from the fridge? & into what temperature wort? I have my fingers crossed. Lusty. Link to comment Share on other sites More sharing options...
ben 10 Posted February 13, 2016 Share Posted February 13, 2016 Was it pitched straight from the fridge? & into what temperature wort? Straight from the fridge. Unsure the exact temp of the wort. It was quite cool last night. Maybe 20°... Link to comment Share on other sites More sharing options...
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