Donate Coffee Blog



RoRについての知識が欠けているとともったので勉強がてら書きたいと思います。Perfect Daily Grindの「Coffee Roasting Essentials: A Guide to Rate of Rise (RoR)」という記事を紹介いたします。


  • 低いRoRはベイクドの原因に

Jen tells me that you don’t want your RoR to drop too low because then you risk reaching the stalling point. A stalled roast happens when the RoR becomes so low that the machine doesn’t want to recover, and the temperature remains the same. This can lead to “baked coffee”, a defect that creates a flat, doughy flavour. In this situation, the coffee’s aromatic compounds won’t be developed.

However, that doesn’t mean a high RoR is best. Your goal should be to control your RoR with precision. And as you learn how to do this, you will find you are able to accentuate different flavours in your coffee. For example, a higher RoR – especially towards the beginning of the roast – can accentuate acidity. Willem Boot of Boot Coffee and Finca La Mula also states that a lower RoR can help modulate sweetness.


しかしそれは高いRoRがベストという意味ではありません。目標はRoRを正確にコントロールすることです。またこの方法を身に着けると、コーヒーの様々なフレーバーを引き立てることができます。例えば、高いRoR(特にローストの始まりに近づく)はアシディティを強調してくれます。Boot CoffeeでありFinca La MulaのWillem BootはRoRが低ければスウィートネスを調節するのを助けてくれるとも述べています。


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  • ベイクドコーヒーとは

Despite what you may have heard about baked coffee being caused by long roast times, negative RORs, or some strange combination of factors, the main cause of baked coffee is a pronounced ROR crash, or more precisely, a drastic change in the slope of the ROR.  Relative to a well-executed roast, baked coffee seems hollower, flatter, and less sweet.  Of course, there are degrees of ROR crashes and degrees of baking.  A roast may be slightly baked or extremely baked, and the severity of the ROR crash will correlate with the degree of baked flavor.


 Qグレーダーコースではベイクドコーヒーを長時間焙煎したものと学びました。しかしScott Raoはこれは間違いだと主著しています。Scott RaoはRoRの急激な低下がベイクドコーヒーを作り出しているのではないかと考えています。



  •  RoRの3つのポイント

Your RoR will change as the roast continues to develop, and there are certain moments that are worth paying more attention to. This includes top/max RoR, crack RoR, and end RoR, stages that professionals such as Patrik Rolf and Morten Münchow have highlighted as critical.

The top/max RoR is the stage after the turning point (remember, this is when the temperature stops dropping and starts increasing, meaning the RoR goes from negative to positive) when the RoR is at its highest.

The crack RoR is the temperature change during first crack. Some roasters struggle to prevent their bean temperature (remember, this is different from RoR) from dipping here, as a result of steam being released from the beans. While you want to avoid this dip, you also don’t want to increase the temperature as that could be too heavy-handed.

As for the end RoR, that is of course at the end of the roast. You want to be careful at this point in time, because the beans will be drier and therefore more brittle.

RoRはディベロップし続けてるにつれ変化していく中で、注意を払わなければいけない瞬間があります。Patrik RolfやMortenMünchowなどのプロが重要視している段階はMax-RoR、Crack-RoR、End-RoRがあります。






  •  RoRの調整

With RoR, there are certain “rules” which are good to follow. Most notably, Scott Rao makes the case for a steadily decreasing one. While stalling will create baked flavours, an increasing RoR – especially after first crack – can lead to a coffee that lacks sweetness.

Yet within these parameters, there is plenty of room for roast manipulation. Jen tells me that there are particular moments during the roast that are suited to adjusting your RoR. For example, the drying and yellowing stages provide you with plenty of time for temperature changes.

In contrast, she explains, “The crucial time is the minute or two before first crack, and right after. At that time, the choices you make can have many more consequences and you need to be very attentive.”

RoRには従うべき特定のあるルールがあります。最も注目すべき点で、Scott Raoは着実に減少する状況をつくります。失速して急減速している間はベイクドフレーバーが生成されますが、逆にRoRが上昇していると(特に1ハゼ後上がりやすい)スウィートネスの欠けたコーヒーにつながる可能性があります。





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