Top cropping yeast and changes

Discussion in 'Homebrewing' started by TooHopTooHandle, Jul 12, 2018.

  1. TooHopTooHandle

    TooHopTooHandle Initiate (84) Dec 20, 2016 New York

    I have been top cropping my London 1318 for several batches now and currently have generation 8.
    Every time I top crop it I get 4 centrifuge tubes that each have about 40ml of compacted yeast
    cake (rinsed very clean with very little debris). Each one of those tubes is enough to make a 1.6liter starter with and brew a 1.075-1.080 beer.

    So I have not noticed any problems with under attenuation or off flavors yet. I will report that generations 5 and 6 produced the best NEIPAs I've made and all batches were the same exact recipe so I could test the characteristics of this yeast. Usually I was averaging about 70-72% apparent attenuation with using mash temps of 154-156 degrees which I was quite happy with for this style because I don't like the beer to dry out too much. The sweet spot for FG on these beers for me is around 1.017-1.021. I find that produces a well balanced flavor/mouth feel for me.

    So I just brewed my NEIPA recipe and used my 8th generation London 1318 (2nd time same results just to make sure it wasn't my process). The yeast performed very well and didn't produce any off flavors that I could detect, but it performed too well lol. I had a starting gravity of 1.063 and a final gravity of 1.008, so that's around 87% AA and I mashed this beer at 155 degrees. For this style that is wayyyy to dry for my liking. I also noticed the beers color was not as bright and vibrant as normal or hazy as it normally is. Don't get me wrong its still hazy, but not as turbid or as people say "orange juice" looking. This also effected the flavor, aroma, and mouth feel. The flavors don't pop with that "juice" type characteristic, the aroma does not flow across the table from the glass like before, and the mouth feel is obviously way thinner from the beer drying out so much. Don't get me wrong its not a "bad" beer, but its not as it was intended from previous batches (around 15-20 of the same recipe).

    I know the easy answer is to just buy a new yeast pack and start over which is what I planned to do, but I was just checking to see if anyone else has experienced this ? or maybe I wasn't as sterile as I thought I was with my yeast harvesting/packaging process. I will detail my process below just to give some insight.

    I use a stainless steel spoon to scrape the krausen with that I boil before use and then also a small stainless steel bowl that I boil before use to put the krausen into. I then take the Krausen scrapings and add it to my 2 liter flask that I boiled water in and make a 1.5 liter starter out of it ( I do this make some extra yeast to package for future batches so I don't have to top crop every batch) I then package it in brand new sterile 50ml centrifuge tubes. I use brand new sealed sterile syringes and blunt tip needs to fill the centrifuge tubes with.

    I was under the assumption that you could top crop these strains 100s of times before having to start over or only top crop a few time before having to start over depending on brew house conditions and yeast mutations that happen. I'm guess mine mutated in a way that doesn't not serve this beer style well for me or I picked up some wild yeast from my "brew house" during all these packaging processes lol.

    Sorry for such a long post, but I love learning as much as I can about all aspects of brewing so if anyone might have experienced this with top cropping yeast I would love to hear your results
     
    pweis909 and Push_the_limits like this.
  2. TooHopTooHandle

    TooHopTooHandle Initiate (84) Dec 20, 2016 New York

    Just to show some color differences.
    [​IMG]
    Earlier batches color.
    [​IMG]
    Generation 8 batch
     
  3. PortLargo

    PortLargo Devotee (421) Oct 19, 2012 Florida

    I re-use 1318 all the time. Typically I get aa in the upper 70s while mashing around 152. My current batch is on 4th generation and has performed consistently.

    A combination of problems is probably the cause of your higher than expected aa. Most likely (IMO) is you have picked up something wild. I'm equally cautious in my sanitation but randomly some dirty old bacteria seems to slip in. A spike in your aa seems to confirm this. Second cause is your top-cropping may not accurately harvest the complete range of the yeast. The "early flocc'ers" may not be captured in proportion to the "fast popp'ers". This would change the character of yeast. Mutation is possible but probably less likely, at least enough to cause a 15% increase in aa. It's possible to have all three of these problems.

    I never exceed 8 generations, typically it's more like 4 - 5. Unless you are storing in slants I don't feel like 100 generations is a reasonable expectation. You might consider another method of harvesting: instead of top-cropping it's possible to make a larger than needed starter and store the excess. This eliminates the second problem listed above and I think sanitation is easier overall (problem one). FWIW, I've had wild yeast actually improve the character of a Belgian strain. It wasn't intentional, but for two batches it made some very tasty beer . . . then the "wild-thang" took over and it was dumped. Based on my experience, your next brew cycle with 1318 will probably exceed 87%.
     
    TooHopTooHandle likes this.
  4. TooHopTooHandle

    TooHopTooHandle Initiate (84) Dec 20, 2016 New York

    Thank you for the in put it is greatly appreciated :slight_smile: I def plan to get a new smack pack and start over. My guess was also the "wild thang" got in there a little at a time and just kept growing and every time I packaged it would also pick up some additional. Atleast I now know what to expect from this yeast if I keep my process the same. In the end I cant be mad lol I brewed over 20 batches of beer with this $6.99 yeast pack.
     
    PortLargo likes this.
  5. JohnnyChicago

    JohnnyChicago Crusader (791) Sep 3, 2010 Illinois

    In brewing, I am of the opinion that there are many ways to skin a cat. That being said, IMO, your target terminal gravity is too high. I did some testing recently of NEIPAs in the 6-7% range, from around the country and found, with the exception of turbidity ratings, their specs are quite unremarkable. The average terminal gravity was 3.35°, or 1.013, with AA% in the high 70s and low 80s. Right in line with a west coast IPA. There are many tricks to get that velvety mouthfeel, but I’m not convinced that high terminal gravities are one.
    Worth noting that we tested ‘normal’ NEIPAs, and none of those additive-laden ‘milkshake’ abominations...

    Per your original question, as @PortLargo theorized, you probably picked up something funky; likely diastaticus. Even under extremely careful conditions and with frequent PCR testing, it can seemingly grow out of thin air sometimes. The purity of ‘pure pitches’ is one possible suspect.

    The thing is, even if you didn’t pick up a contaminant, your yeast will change over generations. It can get heartier and better at fermenting specific worts. It depends on the strain, but my experience with 1318 points to the 5th or 6th gen. where the likelihood increases.

    Top-cropping actually accelerates this process as it is effectively selective breeding. While much of the yeast is bubbling away at the top, more flocculant cells are swimming through the beer, eating sugars. By only harvesting the top, you ensure that you collect the less floccing cells, but actively alter the nature of the yeast each harvest. For this reason, many top croppers only go a couple of generations, if they harvest at all.

    Bottom cropping gives the yeast time to finish its work and drop and mix more uniformly. Followed by a slow harvest and separation of the healthy barm (either by eye or through the help of a cell counter like the ABER PerfectPitch), bottom harvesting is usually a much more reliable and efficient method of maintaining a consistent strain.
     
  6. TooHopTooHandle

    TooHopTooHandle Initiate (84) Dec 20, 2016 New York

    Just as a note that is not what I was shooting for a target final gravity. The yeast went above and beyond what it was supposed to. I find 1.020 range is a good final gravity for me with this style. That's why I was concerned with what was going on with the yeast.
    I haven't gone higher on FG yet, but I do plan to keep trying higher to see how much more I can gain. I also am a firm believer that the higher final gravity does play a big role in the mouth feel as well yeast and water profile.
     
  7. JohnnyChicago

    JohnnyChicago Crusader (791) Sep 3, 2010 Illinois

    Oh no, I get what you were saying in the OP. Ironically, the batch that the yeast decided to go crazy on is actually closer to a commercial NEIPA final gravity that 1.020 (just finished too low instead of too high).

    High terminal gravity is one of the things I suspected in these beers because some of them are just so damn thick, but the testing proved quite the opposite. IIRC, the two Treehouse beers we tested were 1.012 and 1.013 with apparent attenuation in the high 70s. Nice dry IPA territory.

    Again, more than way to skin a cat and all that. And the pros certainly don’t have ALL the homebrew answers, but this one seemed pretty open and shut to me...
     
    TooHopTooHandle likes this.
  8. TooHopTooHandle

    TooHopTooHandle Initiate (84) Dec 20, 2016 New York

    Sorry I misread what you were stating. That's crazy their beers finished so low with such a thick mouth feel (I have had several TH beers). I always suspected they were in the 1.017-1.022 range to achieve that thick silky mouth feel with out using any flaked adjuncts(not saying that's a fact, but from the reading I've done they claim to not use any). Proves that the yeast and water are significantly important in the style. Thanks for your input @JohnnyChicago
     
    JohnnyChicago likes this.
  9. EvenMoreJesus

    EvenMoreJesus Crusader (784) Jun 8, 2017 Pennsylvania
    Premium Trader

    Good gravy!

    If you did not have any off-flavors, I would not expect contamination. Impossible to tell without microscopic examination or, more accurately, PCR, but contaminants like other yeast genera, bacteria, or even var. diastaticus tend to leave calling cards besides lower a lower terminal gravity.

    So the beer was just kinda dull?
     
    TooHopTooHandle likes this.
  10. TooHopTooHandle

    TooHopTooHandle Initiate (84) Dec 20, 2016 New York

    Well I guess with the beer only being 12 days old right now and the last glass I had was yesterday (day 11) maybe there has not been enough time for some of those contaminants to show their "flavor profile". I could be way off here because this type of yeast knowledge is way out of my league at this point lol.

    Well to some people they might not think its a dull beer at all (20oz hops in 6 gallons), but with me having drank my previous 15 or so batch I would definitely say its lacking the flavor/aroma pop that my normal neipa has.

    Do you remember the talk we had about me doing a test and using whirfloc tablet at the end of boil in my neipa just to see the results? Well this beer reminds me of the way that beer did. Just lacking its power, aroma, flavor, color, and mouth feel.
     
    EvenMoreJesus likes this.
  11. EvenMoreJesus

    EvenMoreJesus Crusader (784) Jun 8, 2017 Pennsylvania
    Premium Trader

    While that certainly could be true, off flavors and aromas tend to be there from jump street, as they tend to be produced while the organism is multiplying to maximum cell density. In other words, if another organism was the reason that you had a drop in gravity, they would have had to pass through their logarithmic stage to get there.

    On the other hand, that amount of hops might have obscured the subtle nuances of contamination. It's unlikely, but possible, IMO.

    Very possible that by top-cropping as you have that you selected for yeast cells that were not as affected by polyphenol levels in the wort, so they did not form the necessary protein-polyphenol complexes to make your beer look as it did in previous generations while attenuating more aggressively. I can't really tell from the pictures because they were not taken in the same environment, but it looks as if the newest beer is not as opaque as the other. Is that accurate?
     
    TooHopTooHandle likes this.
  12. TooHopTooHandle

    TooHopTooHandle Initiate (84) Dec 20, 2016 New York

    Yeah the newest beer is not as opaque or as bright in color.
     
    EvenMoreJesus likes this.