Motueka hops. Geraniol oil content?

[Smellyglove]

So, I recently brewed a beer which is kind of my standard house SH APA-procedure.

Except. This time I used MJ M15, instead of us05, and did not dryhop. I used motueka.

Last time I brewed with motueka, I got direct lemon and lime from it. So I thought this hop tastes like lemon and lime.

Anyhow. Just kegged this one. I had to go into the freezer and check if I didn't mistake Motueka for Tettnang. The lime and lemon is vanished, comparing to the last beer. It tastes like a noble hop.

So, "Ok, I just didn't get the biotransformation thing going since I didn't dryhop" Even if I dryhop late, comparing to when you "should " dryhop for biotransformation, which is within a few days after pitch.

But at this point (like two hrs ago) I was still thinking biotransformation, as you'll end up with Beta-citronelool, which is implied by the name, it taste like citrus, so lemon/lime..

But biotransformation is because of yeast utilizing hop oils, it converts linalool in the precense of geraniol, as far as I remember.. So I looked up motueka on ych hops, and bam, Geraniol oil content: 0% - 0%. Which implies that it couldn't be straight biotransformation as I know it..

Is this correct, or is it just that the info isn't available? Anyone else has a source for the oil content of Motueka hops? I guess all hops do contain some amount of Geraniol?

Edit: I reformulated my question so now I see the topic ended up in the wrong forum..

 

[kevinthestout]

I suspect that the data isn't available. All Motueka hops are produced by NZHops and their data sheet is here . If the info isn't on that page then it probably doesn't exist.

 

[Smellyglove]

I suspect that the data isn't available. All Motueka hops are produced by NZHops and their data sheet is here . If the info isn't on that page then it probably doesn't exist.

Awesome, I forgot about this. Couldn't access their site and then forgot all about it, now it works.

 

[Gadjobrinus]

YCH lists the geraniol contribution as 0%. ?

 

[Smellyglove]

I just shot NZ hops a mail asking for the numbers. My guess is too that the numbers don't exist on YCH. So instead of displaying N/A or such, it just displays 0 - 0 % if that info hasn't been entered into the form, my guess.

 

[Northern_Brewer]

So, "Ok, I just didn't get the biotransformation thing going since I didn't dryhop" Even if I dryhop late, comparing to when you "should " dryhop for biotransformation, which is within a few days after pitch.

But at this point (like two hrs ago) I was still thinking biotransformation, as you'll end up with Beta-citronelool, which is implied by the name, it taste like citrus, so lemon/lime..

But biotransformation is because of yeast utilizing hop oils, it converts linalool in the precense of geraniol, as far as I remember.. So I looked up motueka on ych hops, and bam, Geraniol oil content: 0% - 0%. Which implies that it couldn't be straight biotransformation as I know it..

I'm not quite sure what your point is. So Motueka doesn't have geraniol - but as you've seen it tastes of lime, so you don't need geraniol for that lime taste (which makes sense, geraniol is rose-floral). Geraniol is not the only way to get citronellol, and in any case that specific limey taste seems to be in part an additive thing of several different compounds. This Brulosophy article has Moteuka's linalool at 1.5-1.6% which is high - and it coulld well be that all the geraniol gets transformed into citronellol and related compounds in the hop. So the yeast doesn't have to do anything to get that citrusy smell. I've not used Motueka myself, but I guess you can get that lime just from rubbing the hops themselves?

Last time I brewed with motueka, I got direct lemon and lime from it. So I thought this hop tastes like lemon and lime...This time I used MJ M15, instead of us05, and did not dryhop. I used motueka....The lime and lemon is vanished, comparing to the last beer. It tastes like a noble hop.

So you brewed one way, and got lemon/lime.

Then you changed two things, and lost the lemon/lime.

So the obvious thing to do would be to go back and test the two changes in an either/or format. It could be the yeast, but it looks like not dry-hopping is the obvious problem, you've boiled off the terpenols and not replaced them by dry hopping. Nothing more complicated than that. What hop schedule did you use on this last batch??

 

[Smellyglove]

I'm not quite sure what your point is. So Motueka doesn't have geraniol - but as you've seen it tastes of lime, so you don't need geraniol for that lime taste (which makes sense, geraniol is rose-floral). Geraniol is not the only way to get citronellol, and in any case that specific limey taste seems to be in part an additive thing of several different compounds. This Brulosophy article has Moteuka's linalool at 1.5-1.6% which is high - and it coulld well be that all the geraniol gets transformed into citronellol and related compounds in the hop. So the yeast doesn't have to do anything to get that citrusy smell. I've not used Motueka myself, but I guess you can get that lime just from rubbing the hops themselves?


So you brewed one way, and got lemon/lime.

Then you changed two things, and lost the lemon/lime.

So the obvious thing to do would be to go back and test the two changes in an either/or format. It could be the yeast, but it looks like not dry-hopping is the obvious problem, you've boiled off the terpenols and not replaced them by dry hopping. Nothing more complicated than that. What hop schedule did you use on this last batch??

I didn't get any lime from it without the dryhop. That's why I now belive the data for geraniol content I found is wrong. It might be the yeast, but for now I belive it's the lack of the dry hops.

My main hop charge for anything hoppy is in the WP at 60C, so I won't boil off (to much of) the oils. I add bittering to taste, then a small amount at 10 minutes to get the deeper hop flavors sort of embedded into the wort, rest is WP and DH.

AFAIK you need both geraniol and linalool in the presence of yeast to get citronellool, through that pathway. If one is missing you shouldn't get that pronounced lemon/lime-taste I got the first time. It was huge, for the little amount of hops I use for my Single Hop-series. 1-2-3. 1g/l @10, 2g/l@WP (60C), 3g/l @ DH.

 

[Gadjobrinus]

I just shot NZ hops a mail asking for the numbers. My guess is too that the numbers don't exist on YCH. So instead of displaying N/A or such, it just displays 0 - 0 % if that info hasn't been entered into the form, my guess.

Probably so.

 

[Northern_Brewer]

it converts linalool in the precense of geraniol, as far as I remember..

AFAIK you need both geraniol and linalool in the presence of yeast to get citronellool, through that pathway. If one is missing you shouldn't get that pronounced lemon/lime-taste I got the first time.

No - you're getting confused. You don't need the "presence" of geraniol to act as some kind of catalyst for the conversion of linalool. I think you're getting mixed up with the suggestion that the taste of a mixture of the three terpenols is different to the components on their own, there's a synergistic effect of tasting the three together. Although geraniol and linalool are floral on their own, their presence makes the citrus of citrenellol taste more limey.

You're still ignoring the fact that plants are capable of making citrenellol on their own (qv..umm Citronella, but also eg kaffir limes), and that even if yeast are making it from chemicals in the hops, those precursors in the hops need not be geraniol, it could be geraniol acetate (which Motueka has high amounts of, but which doesn't count towards the geraniol assay), or tied up in glycosides or whatever.

 

[Smellyglove]

That's how I understood that the citronellool is made, through that geraniol - linalool pathway atleast. I'll do some more reseach on that subject, thanks for pointing that out for me.

 

[bierhaus15]

This is not a popular sentiment, but there is little evidence of significant biotransformation of hop oils occurring with most sacc yeast strains; so little in fact that changes in perceived aroma/flavor is typically due to process or ingredient choice and not because of biotransformation. That is, unless you are adding betaglucosidase enzymes, and even still that is pretty minor in beer.

 

[Smellyglove]

This is not a popular sentiment, but there is little evidence of significant biotransformation of hop oils occurring with most sacc yeast strains; so little in fact that changes in perceived aroma/flavor is typically due to process or ingredient choice and not because of biotransformation. That is, unless you are adding betaglucosidase enzymes, and even still that is pretty minor in beer.

I have also feel that biotransformation has sort of been blown up. But pr now this is the only logical thing from my knowledge I want to point a finger at since I lacked the lemon/lime in the last batch.

You have to start somewhere and exclude or include things from there. Only more brewing of the same recipe can tell me how it works.

 

[Northern_Brewer]

This is not a popular sentiment, but there is little evidence of significant biotransformation of hop oils occurring with most sacc yeast strains; so little in fact that changes in perceived aroma/flavor is typically due to process or ingredient choice and not because of biotransformation.

That's a fashionable sentiment. Geraniol concentrations seem to vary dramatically depending on when dry hops are added - so for instance see figure 4B of this paper where geraniol concentrations drop >80% peak-to-trough if you add Bravo before pitching, whereas geraniol rises slightly if you add it after fermentation is done. Conversely B-citronellol, a downstream product, goes from essentially zero to ~50ug/l if you dry hop before pitching, and you get far less if you add after fermentation is done but leave it on the yeast for a while.

Now you can debate whether those kinds of changes will have a sensory effect, but it's kinda hard to explain those differences without invoking yeast making citronellol from geraniol.

 

[Northern_Brewer]

That's how I understood that the citronellool is made, through that geraniol - linalool pathway atleast. I'll do some more reseach on that subject, thanks for pointing that out for me.

Geraniol can be converted into citronellol, and geraniol can also be converted into linalool. But you don't have to start with geraniol itself, and that step can happen in the hop plant and not necessarily in your wort.

 

[Smellyglove]

Got ananswer from NZ Hops. About 0.535 Geraniol (%) for 2016 Motueka