help with a forced fan oven
Hello to the fresh loaf community
I am trying to set up a small artisanal bread business.
Due to various circumstances, my oven is a gas fueled, forced fan oven. It has room for four trays of 60x40 cms. I have made some tests. Its good for pastries and crusty grissini, but my main product was supposed to be sourdough wholegrain breads and, as you can imagine, I could not get a good result with it.
The summary is that the flavour is good, but the structure of the crumb and the crust are a mess. Almost
I need to find a way for my oven to get a good result and a very good oven spring. My sourdough is still young, but It works very good. I have read similar other threads in the forum related to similar situations. I have the possibility of buying stone bricks or steel trays to give the my loaves the accumulated heat at the bottom they require , but I am worried about if doing so, I could interfere with the thermostat mecanism or some unexpected problem. Another thing is that the heat tend to go up. What would happen? Could I get the loaves burnt in the upper tray?
I tend to think in the stone/steel as if it was a kind of a battery that accumulates the temperature you select in the oven chamber. Once the stones reach the desired temperature... (i.e. 240 ºC) the added stones only would maintain that temperature, gradually liberating the heat if I would switch the oven off. Am I right, or may be the stones or steel would rise the temperature? All these concerns go round and round inside my head.
I need to start selling my products soon, and I have spent more than I expected. I think the steel could be easier to work with but is more expensive. I have no experience with this issues and I would like to be sure that if I invest the money (whether in stone or steel) that would be useful. Otherwise I will be in trouble.
Thank you very much in advance
Pablo
but I think Mark Sinclair has gas+fan ovens and he seems to get good bread.
I think gas + fan is unusual in the UK where I am, but I've not had a gas oven for some years now, so I don't know what the technology is like now...
2 of my ovens are electric + fan and I get good results from them - one I have fitted with 3 10mm thick steel plates though. I heat that to 250°C then turn it down to about 210°C about 10-15 minutes after loading the dough.
The temperature shouldn't rise more (with plates, etc.) - unless the thermostat isn't working.
But maybe if you post a bit more information - what do the breads come out like? What sort of hydration? and so on. Post some pictures if you can.
-Gordon
I've been struggling too, baking sourdough a convection oven. I generally get good results using a Dutch oven but am limited to one loaf at a time. So based on the same principle I cook the first few minutes with the oven switched off and then switch back on to finish the bake. With bricks and pizza stones in the oven for thermal mass and an initial temperature of 250C I can switch off for 8 minutes with 4 large loaves and the temperature drops to about 180C. I then set it to 220C and bake for a further 25 minutes, turning the loaves over 5 minutes from the end. I've tried with and without steam - doesn't seem to make too much difference so I go without as the oven stays hotter for longer.
Yours looks like my small oven - fan at the back with a circular element round it? (guessing at that part - both my fan ovens are like that with fans with circular elements)
My small one is 2.2Kw and max. 250°C. I crank it right up and leave it for about 30 minutes before putting the bread in. I can cook 2-3 large loaves in it and 3-6 small ones without too much difficulty.
What I do: Load the bread in, leave it to 250°C, throw a cup of water in the tray on the bottom and let it roast for 12 minutes. Then I turn it down to 210°C, briefly open the door to let me turn the tins or loaves round, then let it finish off for another 20-25 minutes.
That gives me good results. (I don't use DO's cloches, etc. just bread on/in tins or silpain mats)
The 2.2Kw heater does struggle to get the temperature back up to 250 though. I have graphs of it dipping down after loading the dough into it, then it never actually reaching 250 in those 12 minutes. It's a tough call for a little 2.2Kw heater - you're effectively asking it to boil a few kilos of water (dough) or at least set the crust which will them form an insulating layer to the insides which will them cook a little slower at a lower heat...
Maybe try leaving the heater on at 250 the next time?
-Gordon
Thanks Gordon. I think the oven is the type used to bake off part cooked croissants etc. The fan is pretty intense, you can see semolina blowing around inside in little eddies! Cooking with the fan/element from the start pretty much kills the oven spring - even using the steam injector, probably the crust sets too quickly. The above method though seems to give reasonable results:
but not a patch on the DO where I get something like this:
Hello again guys:)
Gordon, I cannot show pictures at this moment, but I can describe the result: Two pieces of dough 900 g. only reached 3 cm. in height. There where some burnt blisters on the crust and some too big holes in the crumb. (flying crusts?)
I ate all the bread,though. The smell and taste was very good.
This is the basic formula I used:
- flour-----100% (half of the flour 100% extraction rate, the other half, 85%)
- water----69%
- salt-----2%
prefermented flour-----50%
final recipe:
flour-----555g.
water---213g.
sourdough----1477g.
salt------23g.
At first, I refreshed my starter (chef) and let it ferment for 8 hours at room temperature. Then, I added more water and flour until reach the desired amount of starter for the recipe. Then I let it ferment the whole night at 12 º C temperature. The hydration of the sourdough was 100%. In the morning the starter looked right and tasted slighty acid.
I mixed, kneading french style a bit, then rest 5 minutes, and knead a little bit more.
first fermentation: 1 hour and 45 min, 24 ºC temperature. two folds.
second fermentation, 1 hour.
The dough looked and felt right, since the beginning, and during the first fermentation. When I was about to cut and shape, the estructure was very sticky and too extensible. In the oven I firstly used 250º C and poured some boiling water in a tray with steel inside. After 10 min. I set 210 º C for the rest of the baking.
My conclusions:
Such a big amount of sourdough was too much, the dough got overfermented at the end of the first fermentation.
The ovenspring was so bad because of a lack of thermal mass in the base of the loafs, and I realised that the temperature had fallen a lot while I was pouring the hot water too...
In the next test, I have used some firebricks 3 cm thick and reduced the percentage of prefermented flour and the temperature to 22 º C. Heated the bricks to 250 ºC but after loading the temperature had fallen to 200. The ovenspring was so much better anyway. The thermostat worked good.
I am glad, because I am solving the question. Now I think about how to reduce the rapid loss of temperature, and how to get the steam in a more efficient way. Anothe question is: What will happen when I increase the weight with more dough and firebricks until reaching 60kg??? Will the structure endure the weight?? I hope so.
Thank you so much
One thing I may not have mentioned is that I rotate the breads at the point of turning my ovens from 250°C down to 210. So turn thermostat down, open door, turn breads 180° then close the door and carry on...
Without that I did get some very hot blistering. Modern fan ovens are supposed to stop that happening, but when the fan is blasting scorching hot air directly onto something it gets sort of scorched... It's much better in my computer controlled oven though when the heater is only on for a second or less rather than on for 1-2 minutes with the mechanical thermostat. (but I still turn the loaves in that one too)
The ovens ability to stay hot when you load it is going to depend on many things. One is the stored thermal mass - steel plates, stone slabs, bricks, etc. as well as the power of the heater. Loading up an oven with a few kilos of dough and expecting it to get back to full temperature on loading is somewhat hard on the oven unless it has a stupidly powerful heater. You also need to check the bricks you're putting in - they might get hot, but if they store that heat for a long time, then they might not be adding much to the oven. I think thinner "pizza stones" or steel plates might be better here.
My electric kettle is 3Kw and it can boil a litre of water in under 2 minutes - extrapolate that down to a 2Kw heater (what my oven has) and up to nearly 4Kg of water (4 large loaves!) and even without doing any calculations it suggests it's hard to get back up to temperature quickly. Some ovens I've seen in the UK now have 4.5Kw elements - I just hope they have much better hot air circulation, else it's toast time!
I have some graphs of my computer controlled oven dipping down to under 200°C (from 250°C) when being loaded with bread - and it never getting back up to that 250 in the 12 minutes or so before I turned it down to 210...
I can't work out your recipe though - you have almost 3 times the sourdough levian to fresh flour?
This is a blog post I did here a few months back - it's got quantities, etc. it may be of interest:
http://www.thefreshloaf.com/node/44111/easy-sourdough-part-1
I made 6 of those up last night, baked & sold them this morning...
-Gordon
idly watching some videos to get some ideas for myself and saw this:
https://youtu.be/WdQX7BlYQ6A?t=320 it's a few seconds after he finishes loading the oven with baguettes (made in a machine - rewind to see it!) anyway, he then rotates the trays of croissants, etc. in a commercial fan oven... So it seems that even posh ovens needs some attending. I know my commercial fan oven is hotter at the outsides than the middle and always rotate trays during a bake... So basically I think that rotating the breads inside a fan oven is OK - and maybe to be expected, anyway... -GordonI can understand the convenience of rotating the loaves. I have tried a masonry oven, and observed that, once you loaded the loaves, the temperature went up again, because of the great amount of heat accumulated in the stones inside. I am aware that with my set of steel plates, or firebricks or whatever, that effect is extremely difficult to replicate. Probably impossible.
In an oven with just one tray, you will loose temperature, but as I want to use three trays, so that loss is going to be bigger. What I expect is get a temperature of at least 230 º C after I have loaded the oven. I can heat the stones until a higher one, (i.e. 290 º C) load the oven, close the door and hope the stone is hot enough. For that purpose, I thoght I needed a surface that maintained the heat long enogh, but you say something that might change my point of view:
You also need to check the bricks you're putting in - they might get hot, but if they store that heat for a long time, then they might not be adding much to the oven. I think thinner "pizza stones" or steel plates might be better here.
I am not sure I have properly understood what you meant (I am not a native english speaker) The key is "they might not be adding much to the oven". What do you mean? Why do you think thinner pizza stones or steel plates might be better? Is because the could raise their temperature sooner than the firebricks 3 cm thick I have tested?
I appreciate your advise and all you have said to me. I think that with that info and my tests I can do it.
Thank you!
Pablo