PSI Bulletin: November 2025
No. 11/25 SUBSCRIBER EDITION
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Dear Reader,
Welcome to November's Synopsis - the monthly bulletin from Potato Storage Insight. There's an extensive summary of what we've been up to lately below with lots of new opportunities for you to get involved in matters storage. Plus there's topical best practice guidance and technical insight on roof space heating to follow with a few snippets and forthcoming events as usual...
PSI activity
We start this edition with a run down on our recent activities as October/November has been a busy period.
BP2025 exhibition, Harrogate, 19/20 November
Thank you to all those who visited our stand at the recent BP2025 exhibition. We had a great couple of days, with an especially busy Wednesday.
Potato Storage Handbook launched
A key part of our presence at Harrogate centred around the launch of the new Potato Storage Handbook (pictured, left) on the first day of the Show.
PSI has joined forces with Warners Publications, the publishers of Potato Review magazine, to bring you this new reference and advisory standard. The content is compiled by Adrian Cunnington, who previously penned three editions of the levy-funded potato store managers' guide, and Stephanie Cornwall, editor of Potato Review.
The new format, fully updated handbook follows a similar style to previous guides but brings in some relevant commercial advertising to the mix. This reflects the need to secure external funding for the guide, so that it can continue to be made available free of charge to potato producers and store managers.
The content was launched in hardcopy but will also be made available online too. See https://britishpotato.co.uk/industry-updates/the-potato-storage-handbook-2025-2026-edition/
PSI would like to thank all those who helped in the production of the Handbook in any way, from the team at Warners to the growers who gave up their time to let us take photos of their stores. You know who you are and we are very grateful for your assistance.
Potato Store Management Training Course details released
PSI will be involved in two potato store management training opportunites early in 2026.
On 11/12 March, we will be running our own annual two-day, certificated, residential training course at Greetham Valley Hotel near Oakham, Rutland. Trainers will be Adrian Cunnington and Glyn Harper. For details, please email adrian@potatostorageinsight.com for a prospectus. There's a £50 early bird saving available for bookings made before 6 January. The course also offers delegates a chance to take the BASIS Stored Potatoes qualification subject to further tuition and an exam in spring 2026.
Also, early in the New Year, on 14/15 January, Adrian will be speaking at the SRUC Storage Course being held in Perth. Details can be obtained from
British Potato Industry Awards
PSI was pleased to be invited to be part of the 2025 British Potato Industry Awards as a collaborating partner, with Adrian joining the panel of judges for the first time and making an appearance on stage (below, left) to hand over the award for the Best Environmental/ Sustainability Initiative to the representative from winners Puffin Produce Ltd.
SDF/PSI Strategic Potato Day 2026 stands now available
This technical event focusing on storage is now taking expressions of interest for stand space at the event in May 2026.
If you run a storage-focused business and would like to have a presence, please contact either Adrian Cunnington on 07970 072260 or Simon Faulkner on 07850 649719.
New call from CIPC Residues Monitoring Group
CIPC Residues Monitoring Group submits second-year draft report and calls for industry support to secure future potato storage capacity
The CIPC Residues Monitoring Group (CRMG), a cross-industry body, has submitted its second-year draft report with the Health and Safety Executive's Chemical Regulation Division (CRD). The report provides new evidence on chlorpropham (CIPC) residues in potatoes stored during the 2024/25 season and will inform CRD’s annual review of the temporary Maximum Residue Level (tMRL), currently set at 0.35 mg/kg.
The report details residue data submitted by growers, store managers and supply chain partners. In total, 156 sample results were received from potato stores with a known history of CIPC use. Of these, 21 samples (13.5%) contained detectable CIPC residues, all of which were well within the tMRL.
While residue levels continue to decline, the provisional data mirrors Year 1 patterns, reinforcing the need for a temporary MRL. Without it, many stores would exceed the standard detection threshold and be taken out of use, placing significant pressure on the UK’s storage infrastructure and supply chain resilience.
Adrian Cunnington, Chair of the CIPC Residues Monitoring Group, said:
“It is hard to overstate the challenge if we lost our storage capacity; it would be devastating for the industry. We are watching residues come down year-on-year, but the biggest challenge remains getting enough samples. It is imperative that we continue to collect and submit residue data if we are to maintain our supply base for years to come.”
CRMG is now calling on the industry to support a third season of sampling, which will underpin the 2025/26 submission to CRD. Growers and store managers already collecting multi-residue data are urged to submit chlorpropham results from crops stored for at least 60 days. All analysis must be conducted by a UKAS-accredited laboratory.
This evidence is vital to demonstrate the continued need for a temporary MRL. Without sufficient data, stores with a CIPC history remain at risk of being taken out of use.
Adrian added:
“We are asking growers to help build an accurate national picture of residue levels across stores with a CIPC history. By contributing their data, growers will help ensure that the industry can continue to use vital storage capacity safely and responsibly.”
Growers and store managers willing to submit anonymised CIPC residue data can contact the Group by emailing adrian@potatostorageinsight.com
Best practice
Two topics were dominating technical conversations about storage at BP2025:
Much of the talk at Harrogate on this season's storage was focusing on the struggle some ambient stores have been having to get down to temperature. Only in the last few days have we had any appreciably cooler night-time air to enable growers to complete pull-down.
The other 'hot topic' was sprout control with widespread reports of sprouting running out of control due to warm temperatures.
Many growers were reporting that second treatments of sprout suppressants were being made with most products, suggesting that the first treatment applications had either been compromised or had triggered secondary eyes to open.
By now, most stores should be down to holding temperature and ventilation rates can be reduced a little. Reducing fan speeds down to around 70-80% on the variable speed drive (VFD/inverter) will save some money and (providing fans are not under-specified) should still keep a good circulation going. Whatever, ventilation options are available, always maintain adequate circulation to keep on top of an condensation risk.
For specific advice, please call Adrian on 07970 072260.
Technical insight
This month we focus on roof-space heating (RSH) which is incorporated into the design of many stores as an anti-condensation measure.
The function of RSH is to essentially do 'what it says on the tin', i.e. increase the temperature of the roof space.
Why is this important?
Well, in many potato stores the insulating value of the roof can be limiting. This means that, particularly at night-time during the winter months, the roofspace can cool to such an extent that it can no longer carry all the moisture in the air (as cold air has less ability to carry moisture than warm air) and this then results in moisture 'dropping out' on the surface of the structure and/or cooler crop as condensation.
Heating the air does two things: it (i) combats this drop in temperature and (ii) increases the moisture carrying capacity of the air so there is less likelihood of condensation occurring.
RSH is best controlled by a differential thermostat that detects the difference, for example, in temperature between the roofspace air and the surface of the roof panel.
If your store has this facility, make sure it is enabled to keep the crop dry. It is not necessary to wait for roof temperatures to drop before doing so - the likelihood is that you will be too late and it will take longer to dry the roofspace out, increasing the risk of sprouting or rots.
Learn more about condensation control measures in store with the new Potato Storage Handbook, available now.
Snippets
Lukie Pieterse (left), editor of online publication Potato News Today, has penned an interesting discussion article on his PNT website about the future of potato storage. It's written from a North American perspective but raises some interesting points that are very much applicable to the UK and elsewhere in Europe. Take a look at:
Forthcoming events
If you are hosting a potato or agricultural industry event, please send details to admin@potatostorageinsight.com. Key dates for your diary with relevance to the potato sector in the coming months in UK and Europe include:
December
Tue 9 - Wed 10 36th Annual CUPGRA Conference, Cambridge
'Looking back to move forward'
Learning with others to explore future opportunities
Robinson College, Cambridge
Contact: admin@cupgra.com
January 2026
Wed 14 & Thu 15 SAC Consulting Potato Store Managers' Course 2026
Contact tel: 01224 711123 or email: sacapp@sac.co.uk
February
Thu 5 SACAPP Conference: for details & registration email sacapp@sac.co.uk
March
Wed 11 & Thu 12 PSI 2 day residential Potato Store Managers' Course
Greetham Valley Hotel, Oakham, Rutland
for a prospectus email: adrian@potatostorageinsight.com
June
Tue 16- Fri 19 European Association for Potato Research: Joint Section Meeting - Agronomy and Post-Harvest - see above
Other storage training opportunities for early 2026 coming soon: please contact Adrian at PSI on 07970 072260 for details.
Please note that you, or a colleague, can subscribe to Synopsis at any time by going to potatostorageinsight.com and clicking on SUBSCRIBE. We can also now take payments by credit card. Call Adrian on +44 (0)7970 072260 if you have any questions.
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Synopsis is written by Adrian Cunnington and published by Potato Storage Insight Ltd., 45 Main St., Gedney Dyke, Spalding, PE12 0AJ. UK.
© Potato Storage Insight Ltd. 2025
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