Episode Five – Peter Giuliano

I really hope people enjoy this one – because I really, really enjoyed the conversation I had with Peter.  We’d planned to talk about some fermentation experiments he’d been working on, but we cover a range of things. Listening back it seems like we planned this more than we had – this wasn’t the case, it was just a little serendipitous.

In this podcast:

- What is fermentation in coffee?
- What can a coffee being “washed” mean?
- Some experiments with fermentation
- Peter’s favourite coffee books
- Variety Vs Varietal

There is more stuff in there too. I think it is a really helpful listen if you want to better understand this incredibly important part of the process. I just couldn’t chop this one down – so if you hate the longer podcasts I’m (sort of) sorry!

You can do stuff like subscribe or leave some sort of rating or comment on iTunes here, or you can subscribe to the podcast feed here.

Feedback always welcome – really hope people enjoy this one.

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38 Comments

  1. Great work James and Peter. Loved it.

  2. age of yeast is sought after by bakers for a variety of reasons. Our Sour Dough yeast is over 40 yrs of age from Poland. There didnt seem to be a forward on this. It would be interesting to know if there was a consensus on a rough optimal time for ferment. Or does it not translate because african drying lower humidity than say Salvador. Did you feel there was a step forward after all that massive effort Peter made?

  3. massively enjoying listen to these podcasts -long or short-

  4. People who aren’t well trained in microbiology really shouldn’t speak about microbiology. The interview is riddled with blatant mistakes.

  5. Our Honduras COE smells amazing green. It’s most amazing attribute is it’s smell on grinding the roasted coffee.

  6. Great podcast.

    In trying to determine the exact nature of the mucilage degradation – ie primarily enzymatic pectin degradation or some other cause – you could employ a specific polygalacturonase inhibitor to at least partially inhibit pectin degradation and to observe whether mucilage degradation is affected.

    In 3 tanks you would run:-

    1. Standard fermentation (inoculated with yeast of choice)
    2. Standard + vehicle
    3. Standard + vehicle + polygalacturonase inhibitor

    Vehicle may be particularly important as from a quick look it seems most known polygalacturonase are themselves proteins, which is less ideal than say a small inorganic compound (eg CuSO4 – itself a pectinase inhibitor but probably too broad an effect to be useful here).

    You could then either
    (a) get someone to overexpress and purify these Polygalacturonase inhibitor proteins – in which case adding to the fermentation tank could be simple.
    (b) get someone to transfect a bacterial strain with the gene for the protein – and you could co-inoculate the fermentation tanks with the bacteria (vehicle) and the yeast of choice. So a wild-type strain of the bacteria would be used in (2.) above to determine any effect due to the bacteria alone and not the transfected gene.

    Just some thoughts… v. interesting subject matter.

    Would LOVE to be at the cupping table when the different inoculated tests are all cupped!!
    Jealous.

  7. I just want to follow up on this comment, and try and bridge the gap between discussion here and discussion going on via email.

    Firstly – I think both Peter and I were very happy to have some honest feedback and this particular subject. While I don’t think (for a second) that we should be considered experts on the subject (which I hope was made clear during the conversation), I think that making mistakes in public is no bad thing if it leads to them being corrected.

    For years much of the theorising in speciality coffee has gone on behind closed doors. We’ve gotten little pet theories that aren’t challenged to the point they’ve become accepted as fact. (i.e. crema isn’t about oil emulsification, despite constant statement to the contrary.)

    I hope some of the results of the discussion between you and Peter resurfaces here – as I think there are plenty of us who’d love to understand this more.

  8. In coffee terms – I don’t think anyone outside of Peter and Aida has done much with experimenting with adding yeasts, so no one has much of an idea what would be good or bad.

    Fermentation time seems tied to temperature – which in turn is tied to altitude, rather than humidity. I think. Anyone?

  9. Will there be a part 2 with Peter Giuliano?

    And stop apologizing for going on too long with the podcasts. I keep thinking it’s way too short.

    Cheers!

  10. I hadn’t planned on a second part – but it would be interesting to follow up with him once the samples have been roasted and cupped.

    I might do a follow up episode that covers a few of the different things raised in various shows….

    As for length – I will be running a quick couple of polls about the podcast, one concerning length of the shows. Glad you are enjoying them!

  11. Re variety / varietal as well as geographical origin. As insiders / geeks we love getting into the detail of all this. I’m not sure however that its the way forward in terms of marketing.

    Though great for geeks, for the rest of the coffee drinkers, even those who really appreciate quality, I think the industry should be careful of over-complicating things and turning coffee into something which becomes daunting to purchase. This is clearly the case in wine, where the diversity is something wonderful to geeks but something stressful and daunting to the (vast) majority of consumers. (Buying wine has been shown to be a stressful thing to do in many consumer studies in many countries – it is too complicated and they are scared of getting it wrong and looking stupid.)

    Not saying I have the solution but I would be wary of holding up the wine industry as a model.

  12. SOME UPDATES!!

    As James referenced, there has been some email conversation going on between me and Dr. Randy Worobo, a microbiologist from Cornell. Andy Schecter made the connection- thanks Andy!

    First, some corrections:

    -It sounds like I referred to Brettanomyces as a bacterium, it is of course a yeast.

    -I mistakenly referred to pectinase as “pectase”. The above two are funny, of course, since James and I spend so much time talking about grammatical correctness!

    Now: a couple of interesting things that have evolved from our conversation:

    -At one point, I made reference to a “colony” of microorganisms in one of the experiments; in the one inoculated with malolactic bacteria. What I saw was a cloudy clump of material just under the surface of the water. Dr. Worobo thinks that is an indication of acetic acid bacteria (these are also called acetobacter, or vinegar mother), and is not associated with the malolactic bacteria nor any yeast. Interesting.

    -According to Dr. Worobo, the most likely source of microbes in the fermentation tank is not the air, but the surface of the fruit itself. This is consistent with what I have read about the way “natural” wine fermentations work. This is a source of interest for me- and an obvious point for more research.

    -Dr. Worobo is a really nice guy, and is just as passionate about microbiology as we are about coffee! He’s interested in learning more about this, and he’s been super helpful in engaging on this topic. I think we might get some answers to our questions! I’ll keep everyone posted….

    Peter

    oh, PS I forgot to mention on the podcast; Tom Owen from Sweet Maria’s did some experiments with Aida a couple of weeks before I arrived in El Salvador, using pectinase in coffee fermentation experiments, with interesting results. Maybe he can weigh in too!

  13. SOME UPDATES!!

    As James referenced, there has been some email conversation going on between me and Dr. Randy Worobo, a microbiologist from Cornell. Andy Schecter made the connection- thanks Andy!

    First, some corrections:

    -It sounds like I referred to Brettanomyces as a bacterium, it is of course a yeast.

    -I mistakenly referred to pectinase as “pectase”. The above two are funny, of course, since James and I spend so much time talking about grammatical correctness!

    Now: a couple of interesting things that have evolved from our conversation:

    -At one point, I made reference to a “colony” of microorganisms in one of the experiments; in the one inoculated with malolactic bacteria. What I saw was a cloudy clump of material just under the surface of the water. Dr. Worobo thinks that is an indication of acetic acid bacteria (these are also called acetobacter, or vinegar mother), and is not associated with the malolactic bacteria nor any yeast. Interesting.

    -According to Dr. Worobo, the most likely source of microbes in the fermentation tank is not the air, but the surface of the fruit itself. This is consistent with what I have read about the way “natural” wine fermentations work. This is a source of interest for me- and an obvious point for more research.

    -Dr. Worobo is a really nice guy, and is just as passionate about microbiology as we are about coffee! He’s interested in learning more about this, and he’s been super helpful in engaging on this topic. I think we might get some answers to our questions! I’ll keep everyone posted….

    Peter

    oh, PS I forgot to mention on the podcast; Tom Owen from Sweet Maria’s did some experiments with Aida a couple of weeks before I arrived in El Salvador, using pectinase in coffee fermentation experiments, with interesting results. Maybe he can weigh in too!

  14. James, what was the music you used at the start of that?

    Also, talking about selling by variety.. Peter mentioned tasting Pinot Noir that didn’t really taste for him very Pinot Noir-ey. Surely to get a good sense of what a Pinot “should” (i hate that) taste like, you’d need to taste Pinot from many many regions and producers. This is why wine is sold with not just variety but also the region and producers name on the bottle(particularly true with Pinot Noir as it shows it’s terroir more than any other variety).
    Even within New Zealand we have such a wide variety (lol) of styles of Pinot Noir, as each show huge influences from their terrior.

    I think it could certainly be helpful to promote the idea of selling coffee with the variety listed on bags, though of course with the region/farm and producer and roaster also listed.

    Sadly the only company I know of here (NZ) really pushing this idea, or indeed even using very interesting coffees, is Rocket. Thankfully they’re only 20mins away!

  15. These podcasts are educational and great. The long conversation with Peter seemed very organic and comprehensive. The short podcasts leave more to be desired. The people who are listening to these don’t mind length. And if they happen to not be interested in a particular subject, they can skip ahead to the next topic. Thanks again for doing this.

  16. Thanks for a great post. Could you please give the full references to the recommended books (three in total during the podcast)

  17. just started the podcast but props on the intro music. i am absolutely in love with that burial/four tet collaboration, i play it in the shop all the time.

  18. I have not listened to the podcast and am also not a microbiologist, but if you’re talking about the “for years much of the theorising in specialty coffee has gone on behind closed doors” as a problem, then isn’t maintaining conversations in email equivalent to being behind a closed door???

    Let’s return to an open forum (such as Barista Exchange) where ideas, theories, discussion and discourse can take place in the open and to the benefit of the community.

  19. Jay, we live in the Twitter age, where some people feel the necessity to tweet relentlessly about their every feeling, meal, and bowel movement.

    But believe it or not, there are still a few folks who find it more productive to discuss new ideas privately, until the ideas are fully-formed and worthy of public presentation.

    Perhaps Peter and Dr. Worobo fall in this second category. Perhaps they’d be a lot less productive if they were forced to deal with every half-brained suggestion made on Barista Exchange or a similar forum.

    Maybe this would be a good time for us to practice a little patience.

  20. I apologize to the group: my use of the words “half-brained” was inappropriate. I didn’t mean to say that potential participants in a public discussion would be dumb; it’s just that they aren’t likely to be experts in microbiology. And bringing in microbiological expertise appeared to be something that Peter is very interested in doing. So for the time being, I think it would be a significant distraction to pursue the project in a public forum.

  21. Ummm… if you scroll down a bit, you’ll see where I update everyone on the email conversation I’ve been having, and promise to keep the updates coming.

    ?

    Peter

  22. I studied horticulture for a few years, and in our plant identification classes we learnt about the “Binomial Nomenclature” or Scientific Classification, wherein a living organism is classified by its Genus and Species. For example a species of Daisy could be Gerbera anandria (Genus + species). A varietal is where within that “species” there are varying characteristics, such as Daisy’s there might be varying colours. eg: Gerbera anadria var. densiloba.

    So within coffee, the Genus and species we talk about are mostly Coffea arabica

    Bourbon’s scientific classication would be Coffea arabica VARIETAL bourbon.

    I’ve heard of other terms such as cultivar. Hybrids are another thing all together which would take to long for me to write about. Usually in the horticultural and botanical worlds they use the term varietal.

    Great to listen to Peter talk.

  23. I wanted to weigh in on the packaging/selling/labeling by location and varietal. In my admittedly small knowledge of the wine industry and an even smaller one of the coffee industry I do see one thing that I think is missed here. When wine is sold by varietal (e.g. Merlot from California) vs domaine (e.g. Bordeux) the subtle difference is that wines produced in a domaine are legally regulated in terms of the mix of the grapes and where the grapes are grown. While both methods of marketing (and make no bones about it that it is marketing) work for different reasons there is something different about a wine domaine. Coffee to my knowledge does not have this. As I understand it someone could sell a bean as X when it is really Y or a mix of X and Y. If the coffee industry is going to go further down the route of location and varietal then there comes the question of the value (to the consumer in terms of flavor/style/etc and to the producer in terms of profit) of establishing legal regions where coffee growth is regulated versus simply stating the varietal and production location.

    The other thing coffee doesn’t have and probably can’t have is the difference between wine made by a negotiant and a grape grower. Wines grown, harvested, fermented and bottled on site are different than grapes purchased by a wine maker who then blends them with other grapes from other areas (in the coffee world this would be Folgers I guess). Since the coffee industry has moved towards single origin (aka wine made where it is grown by the farmer/wine maker) then it probably makes more sense to label the varietal and the location than going the route of a domaine style system.

    That said, if the tops of the coffee industry can’t taste a difference between one varietal and another grown in the same location that there may be little sense in bothering to confuse the customer.

  24. It’s funny that you wrote this now as I believe a current trend in speciality coffee goes against the rules you’ve laid out while very much still being transparently, directly sourced and meeting the criteria of being from a single origin. There are a number of roasters participating in projects with processors that involve many small lots from a specific area grown by many small land holders being cupped and selected to create a sort of domaine coffee. 2 projects specifically that I know of are the hunapu project in Antigua Guatemala and the Las Mingas project run by virmax in Cauca Colombia. Info on Las Mingas, which was started in 2004 an be found at the bottom of this pdf:http://www.virmax.com/site/pdfVirmax/CoffeeMay06.pdf. I found the most succinct and complete information on hunapu on Stumptown’s website http://info.stumptowncoffee.com/coffee/guatemala-bella-vista/. Love this trend as it allows smaller producers to get a premium for their quality they wouldn’t normally get from their quantity.

  25. just wondering whether a processing mill would/could be classed as a negotiant in comparison to a coffee grower like Aida who manages the processing herself – many great coffees have been the result , and often named by the roaster/retailer after the processing mill

  26. You make a good point. I was less than eloquent in my post and it shows my stellar ability to not communicate very clearly. I applaud the efforts on the specialty coffee front to source beans from these kinds of projects, to compensate small growers well and to label the end product with both the coffee company and the grower/region. The subtle difference I would like to try and re-emphasize is that a wine domaine is a legally defined geography that sets down rules for the grape varietals and the blending. Single origin coffee and single vineyard wines are sold with the facts stated but with no legally defined constraints. Is this bad? Nope. I just want to point out the difference in the scope of the discussion of labeling coffees with the varietal as well as the grower, region and coffee company.

    The difference more verbosely expanded requires an example so I’ll use Cotes du Rhone wines. When a consumer buys a wine labeled as such they know the general grape blend they are going to get (see http://en.wikipedia.org/wiki/C%C3%B4tes_du_Rh%C3%B4ne_AOC for more detail). On the flip side, talking about coffee, when someone buys coffee from a roaster that publishes the source they know the geographic region the grower is in and the grower’s name/farm. That does in no way guarantee that the product will be the same general thing each year nor that coffee bought from the farm next door will be the same varietal. Now, please refrain from discussions of yearly variations since coffee is produce and as such varies. Grapes are no different. By labeling the end product with the grower, location AND varietal the consumer has a nice listing of what they are actually buying. Can someone tell the difference? Perhaps, perhaps not. This may have to do with too many variables to discuss here.

    So, what does this all mean? Probably not much. However, going back to my original post and revisiting the second to last item (it makes more sense to label grower, location and varietal) I would like to reiterate that this in my mind makes far more sense than the coffee industry trying to establish controlled growing domains like the wine industry.

    I hope that I’ve not missed your point and I apologize if I have.

  27. Perhaps I missed yours as I very much agree with you. You are right in that it would be easy for a grower to try to pass off a coffee as being from a different region, ie I have heard that more coffee is exported from Antigua than is grown in Antigua. I think this affects the truly specialty segment of the industry less than it might the commodity segment of coffee as cup quality is held in such high regard in our realm of coffee.

  28. ANOTHER UPDATE!!!

    Counter Culture and Aida Batlle will host a cupping of these experiments (and more!) at the SCAA show for anyone who wants to come and check it out. We’ll do it at our pop-up cafe in the lobby of the convention center just after noon on Friday, April 29.

    Peter G

  29. Oh I wish I could be there for that cupping!!! Great discussion guys. The 50+ minutes flew by pleasantly.

  30. Would love to hear how the experiments cupped?  Anyone that was at the cupping willing to share?

    Phil

  31. Would love to hear how the experiments cupped?  Anyone that was at the cupping willing to share?

    Phil

  32. Would love to hear how the experiments cupped?  Anyone that was at the cupping willing to share?

    Phil

  33. Would love to hear how the experiments cupped?  Anyone that was at the cupping willing to share?

    Phil

  34. Simply illuminating.

    Keep it up. We are comfortable with your length.

    As a grower and processor of coffee I was enthralled!

    What was the intro squelch music, I want to buy it on iTunes.

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