A Beginner's Guide to Resting Coffee — Transcript

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1. 0:00today we're going to talk about resting
2. 0:01coffee we're going to talk about the
3. 0:03sort of science behind why we rest
4. 0:04coffee and cover best practices for
5. 0:06resting it for espresso brewing and also
6. 0:08for filter brewing now i think resting
7. 0:10coffee very quickly becomes a point of
8. 0:12anxiety in someone's coffee journey at
9. 0:14the start you understand that fresh is
10. 0:16good and therefore you think fresher is
11. 0:18better and you go online and you buy
12. 0:20coffee from a roaster and they ship it
13. 0:22to you the day it's roasted so you're
14. 0:23like okay great this is super fresh
15. 0:25therefore it is super good and then you
16. 0:27hear
17. 0:28no
18. 0:29maybe not maybe fresher is sort of
19. 0:31better but it still needs to rest and
20. 0:33age a little bit before you brew it and
21. 0:35then you're stuck with the question of
22. 0:37how long should i rest it for what's the
23. 0:38right amount am i am i brewing this too
24. 0:40soon am i missing out something did i
25. 0:41did i rested too long have most of the
26. 0:43good flavors gone what's the right thing
27. 0:45to do
28. 0:46and i think if we understand what's
29. 0:48going on inside the coffee if we
30. 0:50understand how it affects the brewing
31. 0:52process then you can make an informed
32. 0:54decision because a bunch of the factors
33. 0:55that affect resting are kind of down to
34. 0:57you your home your lifestyle and your
35. 0:59brew method let's start at the top let's
36. 1:01talk about why we rest coffee all of
37. 1:03this starts in the roasting process when
38. 1:06you roast coffee there's a bunch of
39. 1:07chemistry going on a bunch of browning
40. 1:09reactions and almost all of those
41. 1:11produce carbon dioxide as a byproduct a
42. 1:14surprising amount of carbon dioxide
43. 1:15you'll often see a study cited that says
44. 1:17a kilo of coffee will produce 10 liters
45. 1:19of co2 during the roasting process now
46. 1:21most of this escapes the coffee bean
47. 1:23during the roasting process now to say
48. 1:25that one kilo of coffee does that makes
49. 1:2710 liters i think is confusing and
50. 1:29actually disingenuous it produces a lot
51. 1:31of co2 but how you roast it especially
52. 1:33the darkness of the roast really really
53. 1:35really impacts the amount of co2 that
54. 1:37you produce
55. 1:38light roasts produce a lot less co2 than
56. 1:41dark roasts the darker you roast the
57. 1:43more of these kind of browning reactions
58. 1:45you have right up until the point of
59. 1:46combustion which i don't recommend
60. 1:48reaching but does produce an enormous
61. 1:50amount of co2 now as i said most of the
62. 1:52co2 does escape the coffee bean during
63. 1:54the roasting process but quite a lot is
64. 1:56trapped inside and over time it will
65. 1:59slowly leach out it'll just sort of come
66. 2:01out of the bean
67. 2:02but there's a couple of factors that
68. 2:04determine this as i said the lighter you
69. 2:06roast the less co2 that you're going to
70. 2:08have but confusingly the lighter you
71. 2:11roast the denser the end coffee bean is
72. 2:14that means the harder it is for the co2
73. 2:16that is trapped inside it to get out now
74. 2:18a dark roast will produce a lot more co2
75. 2:21but the bean can't keep hold of it
76. 2:23because that roasting process has made
77. 2:25it so much more porous the beans puff
78. 2:27out and become less and less dense and
79. 2:29more brittle the darker you roast them
80. 2:31and so with a very dark roast the bean
81. 2:33can't really keep hold of the co2 inside
82. 2:36of it and that's kind of it this is the
83. 2:37thing that i really want you to focus on
84. 2:39which is what coffee do i have again the
85. 2:41higher grown a coffee would be
86. 2:43the more dense the seed is going to be
87. 2:45the slower it will degas now why are we
88. 2:47worried about it degassing in the first
89. 2:49place well when you finally come to brew
90. 2:51coffee water hitting the grounds really
91. 2:53helps liberate a lot of the co2 when
92. 2:55you're making a filter coffee say a v60
93. 2:58you'll see that in the bloom the fresher
94. 3:00the coffee is the bigger the bloom
95. 3:02you'll see as you start to sort of pour
96. 3:04water onto the grounds again this is a
97. 3:06pretty good visual if you take a dark
98. 3:07roast you'll typically see especially a
99. 3:09fresh one a much bigger bloom than you
100. 3:10would see in a lighter roast even if
101. 3:12that light roast is very very fresh
102. 3:14because it just really is a lot less co2
103. 3:17in lighter roasted coffees now while
104. 3:19filtered coffee might be a very good
105. 3:20visual explainer of kind of blooming
106. 3:22about the co2 traps inside the coffee
107. 3:24bean it really causes trouble when we
108. 3:26come to a much more intense brewing
109. 3:28process like espresso
110. 3:30there if you have a lot of co2 coming
111. 3:32out of the coffee and again typically
112. 3:34you're using darker or more developed
113. 3:36roast that will have a little bit more
114. 3:37co2 than say a filter coffee but in that
115. 3:39scenario co2 coming out of the grounds
116. 3:41as the water is hitting can be very
117. 3:42disruptive to the brewing process making
118. 3:45it harder and harder to properly extract
119. 3:47the coffee therefore with both filter
120. 3:49coffee and espresso what we tend to do
121. 3:52is rest the coffee for a period of time
122. 3:54to allow some of the co2 out hopefully
123. 3:56not let any real stalin reactions take
124. 3:58place and then when we brew the coffee
125. 4:00it's easier to brew and it's easier to
126. 4:02extract and ultimately will taste
127. 4:05better before we get into specific
128. 4:06recommendations around resting coffees
129. 4:08for filtering espresso i do just want to
130. 4:10touch on one other thing that i think is
131. 4:11really interesting you can in certain
132. 4:13situations
133. 4:14shortcut the resting period this can be
134. 4:17done actually at the roasting stage in
135. 4:19terms of how you cool the coffee this
136. 4:20was taught to me what must be 15 plus
137. 4:23years ago by tim wendell who had needed
138. 4:25to use a coffee a few days after
139. 4:26roasting in a coffee competition and
140. 4:28what they've done is they'd used what's
141. 4:30called quenching to cool the coffee
142. 4:32traditionally in a lot of specialty
143. 4:34companies coffee will come out of the
144. 4:35roaster into a cooling tray and a fan
145. 4:37will drag ambient air through the bed of
146. 4:39coffee to cool it down to room
147. 4:41temperature within two or three minutes
148. 4:43once you get into roasting very large
149. 4:45batches of coffee you can't actually do
150. 4:47that there's too much thermal mass and
151. 4:49if you don't cool the coffee fast enough
152. 4:51then it can kind of keep roasting in the
153. 4:52tray and eventually potentially catch
154. 4:54fire with darker roasts what you tend to
155. 4:56see there for are called quenching
156. 4:57systems where you spray a very fine mist
157. 5:00of water onto the coffee beans this mist
158. 5:03should hit the coffee beans that are
159. 5:04about 200 plus degrees celsius and
160. 5:06instantly evaporate and that evaporative
161. 5:08cooling really drops the temperature of
162. 5:10the coffee beans very very very fast the
163. 5:13more you quench
164. 5:14the more outgassing of co2 you have at
165. 5:16the same time it seems the coffee as a
166. 5:18whole seems to stale faster when it has
167. 5:20been quenched this is occasionally
168. 5:22useful if you're a roaster and you
169. 5:24really need to brew a coffee very
170. 5:25quickly especially for espresso then yes
171. 5:27you can use just a spray bottle almost
172. 5:29and spray cool the coffee you don't want
173. 5:31to add water to the coffee beans
174. 5:33everything you spray on wants to
175. 5:35evaporate if you leave water in the
176. 5:37coffee beans you will rapidly accelerate
177. 5:39stalin and the coffee will taste bad
178. 5:41pretty quickly this is occasionally done
179. 5:44by unscrupulous people who know that
180. 5:46when you roast a kilo of coffee you
181. 5:47might only get 850 grams out because of
182. 5:51loss of moisture and other things during
183. 5:52the roasting process if you add some
184. 5:54water back in you might end up with 900
185. 5:56grams instead and you can sell water for
186. 5:59the price of coffee but that coffee will
187. 6:00not taste good and it will not age well
188. 6:02but that's maybe not your concern if
189. 6:04you're just trying to make as much money
190. 6:05as possible i can't give you specific
191. 6:07instances of this happening but it is a
192. 6:09thing that you can do should you be an
193. 6:11unscrupulous coffee roaster and a
194. 6:12business person going all the way back
195. 6:15that's kind of the the one sort of cheat
196. 6:17in it to really make a difference to the
197. 6:19speed of outgassing but a couple of
198. 6:21other things do make a difference the
199. 6:22temperature in which you store coffee
200. 6:25really matters
201. 6:26you'll see this when you freeze coffee
202. 6:28you can still have a coffee that at the
203. 6:29end of it has quite a lot of crema when
204. 6:30you brew it it still tastes really good
205. 6:33it's like it's still fresh in many ways
206. 6:36the warmer the environment that you
207. 6:37store your coffee in the more rapidly it
208. 6:40will degas
209. 6:41that can be useful but know that you're
210. 6:43also accelerating other stalin reactions
211. 6:46oxidization all of the things that you
212. 6:47don't really want to happen to the
213. 6:49coffee generally speaking the kind of
214. 6:50room temperature of around 20 degrees
215. 6:52celsius is about as hot as i would
216. 6:54recommend storing coffee though i
217. 6:56understand that in certain parts of the
218. 6:57world in certain situations you can't
219. 6:59store it that cool but just know you
220. 7:01should not rest the coffee as long
221. 7:02because it is degassing that much faster
222. 7:05so you'll have noticed that most bags of
223. 7:06coffee that ship around the world have
224. 7:08in them a little valve you won't always
225. 7:11see it clearly on the outside of the
226. 7:12packaging there might be just a few
227. 7:13holes here what's inside it's generally
228. 7:16something like this it's a very simple
229. 7:17usually plastic valve that allows gas
230. 7:20out
231. 7:21but doesn't allow fresh oxygen in
232. 7:23know that if you let a bag of coffee
233. 7:26degas it does not substantially change
234. 7:28the quantity of oxygen inside the bag
235. 7:30the co2 does not displace air left
236. 7:33inside the bag it'll displace both co2
237. 7:36and air together at a similar ratio so
238. 7:38it's not a cheap way to somehow gas
239. 7:40flush your coffee by having the co2 push
240. 7:42out any air in the bag not true does not
241. 7:45work this you'll see on bags of beans
242. 7:47though it's really truly essential on
243. 7:49bags of ground coffee if you seal a bag
244. 7:51of ground coffee without a valve it will
245. 7:53burst the pressure of the gas coming out
246. 7:55of the ground is usually enough to
247. 7:56rupture the seal on a bag and it just
248. 7:58makes a bit of a mess occasionally
249. 8:00you'll see a bag where the the valve has
250. 8:02failed and you might see a puffy bag
251. 8:04that looks a bit weird that coffee is
252. 8:06totally fine it's not bad it's not
253. 8:08suffering from a lack of degassing it'll
254. 8:10still be degassing at a reasonable rate
255. 8:12uh it might seem a touch fresher when
256. 8:14you very first open it but really it's
257. 8:16not worth not buying or it's not worth
258. 8:19freaking out about if if a valve has
259. 8:20failed though just be aware that if it's
260. 8:22a lot of dark roasted coffee in there
261. 8:24again that pressure may rupture the bag
262. 8:26a lot of people like to use storage jars
263. 8:28like this that's no bad thing they'll
264. 8:29use vacuum chambers like this uh these i
265. 8:32think confuse a lot of people if you put
266. 8:34very fresh coffee into one of these jars
267. 8:36that lets you pull a vacuum and shows
268. 8:38you that you've got a little vacuum
269. 8:39pulled that coffee will degas and that
270. 8:42will sort of equalize the pressure which
271. 8:44means that it looks like the vacuum has
272. 8:46failed that isn't the case it's just the
273. 8:48beans degassing you'll find that the
274. 8:49next time you pull a vacuum it may take
275. 8:52three or four days before it equalizes
276. 8:54and after that it never happens again
277. 8:56it's not a faulty product it's just gas
278. 8:57coming out of the beans you've pulled a
279. 8:58vacuum you've removed most of the air so
280. 9:00even though it looks like you've lost
281. 9:02your vacuum what's happened is you've
282. 9:03basically filled that space that was air
283. 9:05with co2 it doesn't mean fresh oxygen
284. 9:08has gotten in the system hasn't failed
285. 9:10it's just been an equalization of
286. 9:12pressures that was a lot of information
287. 9:14let's wrap this up by giving you those
288. 9:16specific recommendations about aging or
289. 9:18resting your coffee based on the way
290. 9:20that you're going to brew it let's start
291. 9:21with filtered coffee filter coffee isn't
292. 9:23as big of a concern honestly brewing
293. 9:26coffee the next day after roasting won't
294. 9:28taste as good as it could but it won't
295. 9:30taste that bad maybe 20 minutes after
296. 9:33roasting not ideal but certainly the
297. 9:35next day it's it's basically drinkable
298. 9:37and enjoyable but it will get better
299. 9:40after three or four days of good storage
300. 9:42with darker roast if you do enjoy those
301. 9:44then i would wait less time i'd wait
302. 9:46maybe two days but but for light roasts
303. 9:50medium roasts
304. 9:51four or five days is a good starting
305. 9:53point but but i wouldn't worry too much
306. 9:56about trying to rest it to a point of
307. 9:57perfection if you're blooming the coffee
308. 10:00and you're brewing well i don't think
309. 10:02you're going to have a big issue and if
310. 10:03you want to drink it you can drink it
311. 10:05with very light roast very dense coffees
312. 10:07yes you might benefit stretching that
313. 10:09out to maybe 10 days in some cases even
314. 10:12longer the taste of coffee that still
315. 10:14has a lot of co2 in it can be
316. 10:16almost like forgotten sparkling water
317. 10:18where you have a kind of carbonic acid
318. 10:20tang to it there's an unpleasant sort of
319. 10:22sourness it'll be under extracted uh and
320. 10:24it generally will taste a bit sour
321. 10:26overall
322. 10:27occasionally if it's super fresh you
323. 10:29might taste a little bit of almost smoke
324. 10:31but that's really pretty rare especially
325. 10:33with lighter roasts espresso is a much
326. 10:35bigger deal espresso is much more
327. 10:37frustrating and that co2 level in the
328. 10:40grounds has a much bigger impact with
329. 10:42light roasts i would probably be resting
330. 10:44the coffee around 10 days i think that's
331. 10:46a good amount of time to make sure it's
332. 10:47good for brewing you're certainly not
333. 10:49going to start to generate negative
334. 10:50tastes know that there was never that
335. 10:53much co2 to begin with so when you start
336. 10:54to pull shots from very light roasts
337. 10:57your crema might look a little thin
338. 10:59it was always that way
339. 11:00light roasts will never produce a very
340. 11:02thick crema once you get into a kind of
341. 11:04medium roast again
342. 11:05eight to ten days i think is a very good
343. 11:07starting point uh just to let that co2
344. 11:10degas there is just a bit more of it
345. 11:11even if it is easier for it to leave the
346. 11:13bean and then with darker roasts
347. 11:16really a couple of days is probably fine
348. 11:18you know what i mean if you leave it
349. 11:19much longer with dark roasts you've got
350. 11:21a lot of oil exposed on the surface
351. 11:23you've got a very porous coffee bean you
352. 11:24should really be concerned mostly about
353. 11:26that coffee going stale rather than an
354. 11:29issue with the co2 outgassing or the
355. 11:31coffee resting properly so so fresher is
356. 11:33really better with darker roasts again a
357. 11:36reminder that your ambient storage makes
358. 11:38a difference if you are freezing it if
359. 11:40you if you're putting it in a cold
360. 11:42environment maybe you store your coffee
361. 11:44in a cellar or a basement or your just
362. 11:46house is a little bit cooler then you do
363. 11:48need to extend your resting times if you
364. 11:50live in a warmer house a warmer climate
365. 11:52shorten your resting times accordingly
366. 11:55pay attention to the roast to the
367. 11:57altitude of the coffee and i think you
368. 12:00should have all the information you need
369. 12:01to rest the coffee and have a really
370. 12:03great result at the end of it but more
371. 12:05than that don't let it stop you enjoying
372. 12:07your coffee resting it is just there to
373. 12:10make it a little easier to brew it isn't
374. 12:12going to transform a coffee from
375. 12:13disgusting to amazing and you're not
376. 12:15going to miss out on something
377. 12:16incredible if it wasn't there in the
378. 12:18first place but now i want to hear from
379. 12:19you do my recommendations line up with
380. 12:22your experiences i know it's hard to say
381. 12:24what is a light roast what is a medium
382. 12:25roast what is a dark roast but
383. 12:27these are the kind of guidelines that
384. 12:28you're working with have you found
385. 12:30resting to be stressful and frustrating
386. 12:32have you had very different results i
387. 12:34would love to hear from you down in the
388. 12:36comments below but for now i'll say
389. 12:38thank you so much for watching and i
390. 12:40hope you have a great day